Behaviour Ecology Year 3

what decisions do efficient foragers have to make?

what type of food to eat. Where and how long to search for. What type of search path to use. How to minimise the risk - predators are often also prey

Group living

A widespread phenomenon. Wide diversity of species. Ecological importance.

Communication networks: eavesdropping in siamese fighting fish

Very aggressive (in tanks will fight to death). In the wild 1 will back down. If put in different tanks they will display - parallel swimming, tails - will get worn out and backdown. Opaque glass allowing eavesdropper to look in without others seeing. Watching the other pairs fight and seeing who wins. Then fights all finding that they were slower to approach the winner. There was a control where the eavesdropper didn't watch the fight (to see if loser/winner gave any other signals) but this had no affect

Why feed parasitic chicks?

Very few hosts reject parasite chicks as there is selection against making the wrong choice in first breeding season and subsequently rejecting own offspring as chick recognition is learned and the cost of acceptance is lower than the cost of incorrect imprinting. As there is no mimicry for the chick - theory is can imprint on egg straight after laid but there is a period between this to chick being hatched, so if parasitised on 1st attempt would imprint on the wrong species and would have lifetime consequences - cost too high so the gene for chick imprinting would be lost. Parasites manipulate parental behaviour by mimicking vocal of hosts offspring to feed at the level of the entire brood (mimicry is innate). Davies playback experiment: the control - sound of 1 offspring and got feed at low level, with brood and cuckoo parents manipulated to feed at a higher rate. Some species will will reject those that cant mimic volals well - Splendid fairy-wrens abandon ~40% nests parasitized by Horsfield's bronze-cuckoos and all nests parasitized by Shining bronze-cuckoos. Although there is visual mimicary in some species .

Signal modality

Visual - fast, short persistence, can be highly directional. Acoustic - Medium, short persistence, high to low directionality. Chemical - slow, long persistence, high to low directionality. Different ways of sending a signal - ecological circumstances determine which modality evolve. And where the selection pressure is coming from - trying to manipulate the environment by changing the behaviour of others - selection pressure therefore comes from the receiver

preventing detection against predators: Preventing capture (offspring)

Vulnerable young - parents perform broken wing display (avocet, killdeer, plover etc) Terrifying organisms e.g. Bagrus to 'guard', cichlid put eggs near catfish as predators won't go near them, OR brood adoption of young in cichlids - instead of the offspring having a 1/5 chance of being eaten increase it to e.g. 1/20 chance.

white-bearded manakin and sage grouse leks

WBM - males each defend a sapling and bare patch of ground they have cleared - 70 display areas in 150 m2 - areas as small as 1 stick. No defined breeding season they display all year. Display: rapid perch changes, snapping wings, and buzzes, with highly modified feathers which make snapping/buzzing noise. Female chooses a male, mates, and then leaves. Males highly conspicuous black/white compared to females. Mating success highly skewed - male a = 329 matings vs. b = 56 matings and 8 other males shared 52 matings. SG - again higly skewed, only 8 males mate with a getting 50% so not as extreme as above but still v. skewed (Gibson)

Types of parasitism

'Classic' parasites - Can be divided into endoparasites and ectoparasites - greenland sharks live for 4-500 years - blind parasites attach onto them, isopod that attaches to tongue eats their food eventually causes atrophy can manipulate behaviour. Parasitoids - spends portion of development inside a host, typically consumes and/or kills host before emerging, free-living life stage. Brood parasites - exploit parental care of con- or heterospecifics

Why do parents over-produce: replacement offspring hypothesis

(Progeny choice hypothesis, Insurance egg hypothesis). Core set of offspring which parents can usually support and marginal offspring which are expendable - are a form of 'insurance' in case of egg infertility, mortality, etc. - explains obligate siblicide in the Nazca Booby

pressures on group and natural selection

2 behavioural phenotypes controlled by genes. N. selection - selection pressure acts on the individual Faster individuals would be more likely to survive so each generation would have more fast individuals - eventually slow would be selected out. G. selection - selection pressure acts on the group, inefficient groups with competing individuals selected against, efficient cooperative groups selected for. In reality even within both groups there would be individual differences

Optimal signal detection for cuckoo host parasitism

2 frequency distributions of being able to determine signal characteristics of the eggs. If more lenient towards egg markings/colour meaning could keep anything that looks like theirs and only reject really odd looking - cost: could be keeping high no. of parasites. If less lenient towards colour/markings means they might get rid of their own eggs - benefit: no parasitism but cost of potentially rejecting own egg.

Co-evolution of signals from sender and reciver

2 groups of organisms exert selection pressure on each other. Inconspicuous signals when interests coincide(minimalconflict). Evolutionary arms races' when interests differ. Receivers develop sales resistance. Results in exaggerated and conspicuous signals.

Serious or fatal fighting

60% of male narwhals have injuries from fights at 1 point in their lives - they have 3m long horns grow when they hit puberty. 5-10% of male musk ox die in competition each year in head-to-head collisions - could be evolution cuasing harsher fighting (ram head plates) - probs not intentional. Nothing to loose - fatalities occur when skew in mating success is severe so individuals have little to lose by fighting (genetic life or death). Possibly not intentional just don't give up - loser won't give up until they cant fight any longer. Elephant seal - only 1 season when they're big enough and mate with a whole beach - fitness either win or don't mate at all - no benefit to backing down. Polymorphic fig-wasps - all eggs hatch inside fig, 2 male morphs fighters and winged dispersers, wingless dicaptiate rivals 77% dead remaining mate.

What is cooperation?

A behaviour which provides a benefit to another individual (recipient), and which is selected for because of its beneficial effect on the recipient (West et al 2007). However such behaviours pose a problem to evolutionary theory because (all things being equal) they would reduce the relative fitness of the performer of that behaviour and hence be selected against. Animals (e.g. lions, sailfish etc.) hunt in groups, meerkats act as sentinels allowing others to forage. Social hymenoptera have non-reproductive individuals which work "for the benefit of the colony".

Deception in polygyny

A female may not know that a male is already mated but, once she has laid her clutch and the male has deserted, it is too late to re-mate. Might be "Best of a bad job". Experiments Alatalo support the deception hypothesis in female Pied Flycatchers males remate and leave her to return to 1st, fine for 1st as he returns for hatching but 2nd stuck.

Sexual selection

A form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates - increasing success but may reduce survival and often run counter to natural selection - e.g. colouration - should camouflage with the environment - driving in different directions. Traits e.g. chemical, pheromone or colouring pattern. Ornaments, weapons, elaborate displays, etc. Two general classes: male-male competition and female choice. Mandril - ornamental teeth - not for eating but for fighting or size dimorphism

male-male competition for mating

A form of sexual selection in which males compete with one another directly or indirectly for access to females as females are the limiting sex. Leads to evolution of secondary sexual traits e.g. horns - evolve for contests between males. Direct combat e.g. elk, big horn sheep, elephant seals, giraffes, etc. Leads to sexual size dimorphism - 10x. Hawk-Dove game - violent contests rare but circumstances where benefits outway costs e.g. elephant seals. Can lead to highly skewed distribution of males fitness. E.g. Elephant seals - no. of offspring produced (1 season) dropps rapidly for each male - large no. of individuals with no reproductive success

sperm competition

A form of sexual selection that arises after mating, when males compete for fertilization of a female's eggs. As well as pollen competition. Found in virtually every taxon e.g. corals, with internal/external fertilisation. Most research on birds - extra-pair paternity in socially monogamous birds 0- >50%. Even though 90% of birds are monogamous Tactics - First vs. last male advantage, raffle (more sperm), sperm displacement. Testis size correlated with levels of EPCs. Male dunnocks peck female's cloaca to stimulate ejection of sperm and mate guard.

sexual conflict

A general principle in behavioral ecology. Occurs between members of the same species as they attempt to maximise individual fitness. Different roles have different ways of maximising fitness e.g. old/dominant - defend, young/subordinate - sneaky. Types of conflict - owners/intruders, Old/young, parents/offspring

Parasites and host behaviour: Sacculina

A genus of parasitic barnacles - free-swimming form attaches to crab & enters its body via a leg joint Inhibits moulting - prevents crab from growing or regenerating lost limbs Disruption of endocrine system inhibits reproduction - diverted to Sacculina reproduction. It bulges out of crab brood pouch disersing their eggs

communication networks

A lot of animals live in social groups so there are more signals and communication if more individuals are involved. In theory communication can work in networks but difficult to obtain evidence

Sequential polyandry

A mating system one female mates with multiple males within a breeding season, but with only one male during each successive nesting attempt. Female spotted sandpipers arrive on breeding grounds before males and fight to establish territories - smaller males incubates clutch while the female defends the territory and courts a 2nd male poss 3. Abundant food and precocial young and minimal cost to parental care - as offspring are highly mobile when they hatch. Females fight for territory

Coefficient of relatedness ( r )

A measure of genetic similarity. The average proportion of genes shared by related individuals.

marginal value theorem

A rate-maximizing forager will choose the residence time for each patch type so that the marginal rate of gain at the time of leaving equals the long-term average rate of energy intake in the habitat. It has been applied to many other traits: duration of mating, mate guarding, size/no. offpring, diving patterns of air-breathing animals.

sex role reversal

A reversal in the usual mate-choice and competitive strategies for access to mates adopted by males and females Females then compete for access to males, males show greater mate choice than females. Stronger sexual seleciton on females compared tom males. It is NOT a reversal in anisogamy as this would just be the opposite sex

what type of search path to use?

A straight search pattern should be best for covering distance quickly. Especially in hostile environments. But a pattern with lots of turns may allow well known areas to be exploited better. Efficient predators should forage in the way best-suited to the conditions - they may switch.

Parasitism

A symbiotic relationship between a parasite and its host - non-mutual: the parasite benefits from relationship, while host pays cost. One or more stages needing a host: parasitic & free-living stages - simple & complex. Across all Phyla. Hyperparasites - parasiting a parasite. Parasites are diverse and ubiquitous: • ~20% of known species are parasites. Animal-animal parasitism evolved min 60 times (found in plants & fungi). Lafferty's estuary studies found mass of parasites equalled fish and almost 10x birds. Ubiquitous - all animals contain parasites. Adult/egg Stage - transmission depends on host activity. Cystacanth stage -transmission depends on ingestion of host As the severity of harmfullness increases, transmission increases

Cooperative breeding

A system of breeding characterised by the normal presence of helpers at some or all nests. Helper - an individual that performs parent-like behaviour toward young that are not its own offspring. Found in a wide range of taxa, but distribution is patchy and wide range of social systems. Dispersal usually delayed due to ecological constraints. Helping often best understood through kin selection, but direct benefits are possible.

Parental care

Any action by which an animal expends energy or assumes risks to benefit its offspring (e.g., nest-building, feeding of young, defense)

Signal Detection Theory

Ability to differentiate between important stimuli (information-bearing patterns) and random noise Responce to novel organisms: Good and bad options (safe vs dangerous, food vs toxin) Difficult for animals to tell them apart (imperfect cues) e.g. if a new organism in the environment is it predator/prey. Response to stimuli will depend on adaptations to environment and experience (proximate/ultimate factors).

Predation as a selective force: Tadpoles

Adapt behaviour/phenotype in response to changes in threat level. Common frog tadpoles grown in the presence of a key predator developed wider bodies and shorter and wider tails, and were less active than those without predators - good defensively, but has costly as wider is harder to fit predators mouth but is costly to develop. But when predators removed, the tadpoles switched back quickly showing reversibility of predator-induced plasticity and its effect at a life-history switch point - behaviour change within 1 hour and morphology 1 week (Oikos).

How do males manipulate the duration of copulation

After mating sperm could be replaced by another male. Mate guarding is 1 way to minimise sperm replacement - but is costly and time consuming. Alternative is to prolong so more sperm is transferred but this doesn't benefit females. Spermatophore transferred without the male being there - its 6% of the males weight, ampulla - contains sperm, spermatophylax - contains water/amino acids - fairly cheap to make to manipulate female behaviour. Hardly any nutritional value but females take 40mins to eat and 12 to rest - amount of time for the sperm to go into reproductive tract. Contains amino acids that stimulate feeding and tiredness. Sahaluk - no. of sperm transferred increased with time ampulla attached and time spent feeding up till 55 mins

Habitat saturation model with cooperative breeding

All suitable breeding habitats filled. Individuals are forced to delay dispersal. Pruett-Jones - experimentally tested in superb fairy-wrens by removal of breeding adults.

Lek: Black hole model

Also named the Female harassment model - harassed by young/inexperienced males forces females to move finding shelter in leks. However limited support - in this deer species likely but in general little support.

Hamilton's rule in P-O conflict

Altruism will be favoured when rB>C Where r is the coefficient of relatedness, B is the benefit to the recipient, and C is the cost to the donor. Conflicts among kin will arise whenever demand outstrips supply. Selfishness is favoured when rB<C - when parents get greater fitness benefit by feeding offspring than they would get by eating food themselves. E.g. if mother has 2 prey items - offspring eating 1 item would icrease fitness by 4 units - 2 by 7 units - parental optimum is to share the food equally between both (4 > 3.5); but perspective of offspring fitness maximised if they receive all the food. Female perspective splitting food equally is more beneficial as gets 4 units of fitness compared to 3.5

Mate guarding by males

Amplexus. Males may have to subdue females in order to mate. Males can maximise their fitness by preventing other males from accessing female gametes - avoiding sperm competition/replacement. But male ownership removes female choice so females should resist. Could last from a few mins to several weeks.

Parental care and game theory

An alternative approach is to use game theory to examine the costs and benefits of parental care from the point of view of both parents. In game theoretical model not looking for 1 perfect strategy for all as the best strategy for 1 individual depends on what others are doing e.g. if 1 parent leaves the other says. ESS models help to clarify relevant factors under a range of different circumstances. Looking at balance of cost and benefits e.g. in what circumstances does it pay to abandon, for one parent to provide care or both. Parents have to determine the probability of survival of offspring if 1/both parents abandon and if males can remate might be more likely to anbandon.

optimality theory

An animal should behave in a way that maximizes benefits of a behavior minus its costs. Used often to determine prey choice e.g. cost of catching prey differs depending on the circumstances e.g. distance, energetic expenditure, probability of failure. Optimality models: prey choice, patch residence. Competition for resources should select for optimality - or at least eliminate least efficient and is the expected result of natural selection. Genes selecting for the best should be passed on producing perfection - this often doesn't happen. Main currency of evolution is fitness - often have to build models with indirect measures r.g. no. of mates, energy intake (is this a good correlation?).

Evaluating novel organisms

Animals need to adopt a precautionary approach to novel/unfamiliar as may be a predator Timidity/wariness/neophobia can lead to habituation/sensitisation. Neophobia (fear of new) varies among individuals as well as among populations - highly stereotypical conflicted behaviour. Have to balance response to risk: risk-prone behaviour can be costly but so can be risk-averse behaviour - need to maximise 'true' responses and minimise 'false'. Making the correct decisions with true/false positives become more reliable when in a bigger group. Collecting social information or perform predator inspection - approach a threatening organism to gather information e.g. sunfish will go up to the rear (as fish basically constantly excreting) if there is sunfish in excrement then they will know they are prey.

what makes males and females different?

Anisogamy is the key difference. As well as chromosomal differences - differs between species - x/y in humans. Mostly reproductive success for females are based on quality of their mates so have to be choosey meaning not all males mate

Examples of Self-organisation

Ant trail following - 1 departs nest, explores local environment looking for food - after finding ant migrates back to nest leaving pheromones behind as it migrates between nest/food, builds up more pheromone - other ants pick up the trail and gradually it's reinforced by additional pheromone - at 1st random movement and then it's a path. Flocks, shoals, herds follow zonal rules of interaction - using local focus interact with a few near neighbours Rules of interaction: zone of repulsion (move away), zone of orientation (stay in proximity), zone of attraction (keep within certain distance). Radakov studied fish shoaling with predator aviodance - potential threat move quickly resulting in wave of movement as info passes - a cascade of information as responding to nearest neighbours.

Human-Induced Rapid Environmental Change (HIREC)

Anthropogenic change - happening at fast rates. Habitat - change/loss/fragmentation. Invasive/exotic species - predators, pathogens, competitors. Human harvesting/disturbance - eco-tourism, fisheries. Pollution - noise/visual/chemical. Climate change. Evolutionary history (prior experience) drive adaptive response to a stimulus. After HIREC the responce may not be adaptive. Causing ecological traps e.g. frog thinking fairy lights are bioluminescent beetles, beetle copulating with beer bottle, turtle hatchlings moving toward light instead of moon

Agonistic signals

Any social behaviour related to fighting. The term has broader meaning than aggressive behaviour includes threats, displays, retreats, placation, and conciliation. E.g. claw waving in fiddler crabs and roaring contests in red deer

Predator adaptations to overcome large prey

Approx 10% of predators attack prey larger than themselves e.g. epomis beetles - specialists in tackling amphibians - they seem like prey to the frog they go for them, then the beetle eats the frog. Komodo dragons - bacteria in bite allowing infection. Predator weapon adaptations to capture prey e.g. cetaceans use bubble netting and 'sonic boom' and sword fish swipe at fish with their noses to damage them

minimising risk while foraging

As they can also be prey efficient foragers should minimise the risk. Strategies: reduce activity, hide. Both would work but cost for reduced foraging opportunities. Should be a trade-off between feeding and avoiding predators - exact balance may vary with hunger (motivation)

association hypothesis

Association with eggs or young pre-adapts parent to provide care - males are only associated with externally fertilised eggs. If just mating or releasing sperm then association with young is short for both male and female. Female mammals association is long - pregnancy/lactation - so female feels the need to carry on care. Not great hypothesis - doesn't give a good mechanism - even though a female has had a long association why should she carry on?

Evolution of signals: ritualisation

Assumes both sender and receiver benefit. Selection pressure for increasing efficiency of information transfer. Behaviour that initially contains some information evolves into a signal. Patterns become more stereotyped. Behaviour that wasn't a signal but contains some information about the sender evolves into a signal because it benefits both. 1. Intention movements: e.g. dog baring its teeth before attack - benefit both to backdown before fight. 2. Displacement activities: motivated to do multiple things at once so might do something completely different e.g. scratch head if can't make decision, male pigeon that doesn't know whether to backdown or fight might preen (evolved into signal)/ 3. Autonomic responses: e.g. cat sticking up hairs before attack as a result of high blood flow - receiver may backdown.

What are the strategies of game theory?

Assumes contestants can choose from a defined set of strategies. Overall plan of action e.g. deer - roar, parallel walk, antler wrestle; differing from tactics how to implement the plan e.g. rate of roaring, how hard to push. Not individual but evolutionary choice - genotypes being selected for. 3 steps to analyse fighting - specify alternative stratergies, average pay-off for each alternative and find the expected solution. Theoretical model - how much fitness benefits for certain behaviour to find the evolutionary stable stratergy

assumptions Fishers equal investment principle

Assumptions for equal investment: Males/females contribute equally to the gene-pool - correct in most cases. Panmixis (random mating) - often not the case. Equal investment returns from each sex. If fisher's correct deviation from equal returns should not occur. If males/females cost the same sex ratio should be .5.

optimal theory critasisms

Assumptions that evolution produced organisms that are well adapted NOT perfect and not everything is an adaptation. How accurate the assumptions are - need to simplify behaviours for maths behind it and often can't measure fitness directly but can measure e.g. food consumption. The maths is complex to work out mechanisms behind behaviour. Often many factors influencing behaviour at once e.g. foraging affected by predators, hunger (motivation) etc.

Hawk dove bourgeois game

B respects ownership and has similar results to H-D-A. B is the evolutionary stable stratergy when the cost of injury is greater than the value

why study foraging?

Behaviour - influences fitness. Ecology - responsible for complex patterns. Food-web showing interaction between predator-prey

Why do parents over-produce: parental favouritism

Baby American coots have orange-tipped feathers on their backs and throats and bald heads to see blood flushing - could be sign of quality as orange-tipped chicks are fed preferentially with higher growth rates and survival. Manipulations confirm that parents use feather colour as a signal (lyon) - if paint an individual then parents will show favour.

Male vs. female reproductive potential

Bateman's principle - males have a stronger correlation between mating success and reproductive output than females. drosophila - observations between females/males - the males mates, the more offspring - directly proportional to/limited by the females he mates with. Female with 1 male 60-70 offspring produced - no increase with more males - not sperm limited but egg limited - more males doesnt increase reproductive output

responding to novelty (HIREC)

Before novelty - past dangerous and safe situations were easily discriminated through evolution of formerly adaptive threshold - few errors. If exotic predator is similar to familiar dangers naïve prey respond, but if exotic predator is different they do NOT respond. Exotic predators are more likely to be ignored thus drive naïve prey to decline if are very different from familiar predators (looks safe). Can impact both predators and prey

preventing detection against predators: crypsis

Behave in such a way as to reduce conspicuousness e.g. guppies. E.g. through crypsis - matching background colouration - widely used across taxa Only works effectively if the animal moves at the same speed as background - stick insects sway with the twig/leaves. Animals generally have characteristic body shapes - can facilitate prey detection and recognition by predators - necessitates edge/form disruption. Experiment with mealworms and card - disruptive patterns increased survival beyond cryptic pattern - again better than plain black/brown wings (Cuthill). Crypsis not just vision - auditory - furry moth bodies defence against echolocating bats Chemical camouflage -Parrotfish - mucus cacoon at night so predators can't detect while sleeping.

Obligate siblicide

Behavior that always results in an individual killing a sibling or siblings. Where siblicide always occurs e.g. Black eagles, American white pelican. 2 egg clutches with highly asynchronous hatching - eggs don't develop until incubation - birds don't usually start incubation until all eggs laid (or penultimate), but these birds will incubate 1st straight away and these with longer period between laying each - usually 24 hours these 2 days -big effect on development so easily killed. Death of junior chick usually 1-2 days after hatching where it's pecked &/or ejected from nest.

Costs and benefits of foraging

Benefit = energy intake. Cost = time and energy - from searching, handling, digesting. Efficient foragers must make a profit. Economic decision making.

Rate maximisation model for optimality

Benefit curve e.g. environment quality vs prey. Often an assumption is the resource is unlimited. The cost is linear and benefit comes when B>C, benefit is above the cost line. Even if prey was unlimited would get full. Bird finding worms - at first easy to find food (worms at the surface and close by) after have to search further (down/across)

polygyny and female choice

Benefit often differs between the sexes: Some males benefit greatly but not all - large skew in male mating success. Females have little to gain and may lose resources or parental care - as often males busy fighting. Females may chose already mated male due to: no cost to polygyny, polygyny threshold model, sexy son hypothesis, deception (might not know males already mates) or unmated males unavailable. There may be no cost to females if males provide no parental care there may be no sexual-conflict over polygyny OR cost of polygyny to females may be zero if resources are super abundant.

differential investment returns due to environmental effects: host quality

Bigger host = more food = bigger offspring. In parasitoids only females disperse - bigger disperse further. Fitness of females tied to host quality more than fitness of males - as males don't disperse but bigger females can fly further. Mothers don't provide parental care but their behaviour still affects resources (host). If host is small then they produce more males quick flip in sex ratio when host is big enough. Experiement (King) 53/75 species more males in smaller hosts.

Predominant patterns of parental care and mating systems

Birds - parental care from male & female with 90% monogamous mating system. Mammals - parental care from female with 90% polygynous mating system. Fish - parental care from male with polygynous, polyandrous, polygynandrous mating systems - fish - complex mating systems mostly promiscuous - parental care is unusual but often male-only.

when will parents desert?

Both - if cost for care is too large and females might be able to produce more eggs if not providing care e.g. turtles (5/100) survive. Male desertion - Males mammals have a high change of remating but females constrained by their anatomy/physiology (pregnancy/lactation) and not much greater survival with 2. Female desertion (unusual) occurs in catfish, pipefish, seahorse of male uniparental - when females are constrained with reproductive output and often sex role reversal (so male carrying eggs) when males have little chance of remating. Both care - probability of surviving with 2 is greater than just 1, and probability of remating is low.

Brood parasitism

Brood parasites lay eggs into the nests of other individuals. Inter/Intra-specific brood parasitism between generations. Around 1% of bird species are inter-specific brood parasites. Common cuckoo and its hosts with coevolution with egg mimicry & rejection/recognition egg of the host takes a long time to evolve. Costly for the host so evolutionary arms race occurs. Most most studies on avian - think that inter evolved from inra

Hawk-Dove-Assessor game

Building upon the H/D model. A - strategy is to assess opponents resource holding potential. A plays H if they're stronger than the opponent and D if weaker. Meaning they're able to understand inequality of the opponent. AvsA - 50% chance of winning with no injury (stronger will pick H weaker D). HvsA - H 50% chance winning, 50% chance of injury (H will always fight but A will fight if stronger but D if weaker), if A weaker will play D so 50% chance of winning with no risk of injury. DvsA - D wins 50% when stronger none when weaker as if both play D, if D is stronger will win 50%, if D is weaker A will play H and win, overall D winning 25%; A 50% plays H wins, other wins 25% as D so overall 75%. A population of A can't be invaded by HorD so it's evolutionary stable

Marginal habitat model in cooperative breeding

Builds on habitat saturation model. Additional constraint is the lack of habitats of marginal quality. Eliminates the potential for non-breeding floaters. In many cases, cooperative breeding can be seen as a 'best of a bad job strategy' adopted when the opportunities for breeding are limited

Sociality

By some definitions, virtually all animals live in a social context. Any foraging animal influences and is influenced by other foragers, even if they don't directly interact in time or in space, e.g direct competition, depletion of resources, avoidance, local enhancement 5

Cost and benefits of parental care

C - time (esp. with short-lived organisms) - opportunity cost e.g. migrating, preening, feeding, recovering (fattening), energy, survivorship, lost extra matings. Some offspring don't need much care but bird/mammals often need significant care - won't survive without 1-2 parents. Offspring need regular supply off food whereas adults can go without for a longer period Direct energetic cost from obtaining food but not getting to eat it. B - increased survival of young. Parental care should exist only when rB > C.

Cooperation as a by-product

Can arise as a by-product of a selfish act. Cooperation is the best option from a selfish perspective, but also provides benefits to others. Mutualisms in foraging, territory defense, predator detection. Cooperative colony e.g. ants.

plant to animal communication

Can be either used to attract or deter animals. E.g. flowers to advertise pollinating insects who see in UV light

Parasites and host behaviour: maximise likelihood of transmission - trophic transmission

Can enhance their likelihood of transmission from intermediate to definitive host if they can: Alter the behaviour of the intermediate host so that it is more likely to encounter the definitive host. Exploit the perceptory system of the definitive host so that it is more likely to detect the intermediate host.

preventing detection against predators: Preventing attack (signalling)

Can help prey animals to avoid being attacked - showing quality and that they can waste energy on other behaviours when predators chase them. E.g. 'pursuit deterrence' - stotting (jumping) in Thomson's gazelles and larks often continue to sing even when they are being chased by a predator.

Parasites and host behaviour: Emerald cockroach wasp

Carefully selects a victim and delivers 2 stings to the cockroach's brain - 1st causes brief 2-3 minute paralysis, allows wasp to perform the second sting - requires much more precision (hence the need for the 1st). Wasp injects directly into the subesophageal ganglion (actively searches with ovipositor for this region). Takes its blood to determine the how affective the sting was - too much and they may die too soon. Then takes the roach into burrow and probes the body to lay the egg and leaves for the young to eat, blocking the whole

intentional damage to females during mating

Caused by spiked penis to female genital tract - causes scarring reduces extra copulation and survival causing hyperovulation. Chemical warfare in drosophila - in male seminal fluid inducing hyperovulation males get more offspring but females shortened life - evolution for female resistance. Hermaphrodites - both attempting to inseminate each other - less expensive for the male - they have no opening so seminal fluid is deposited and dissolves into the epithelial tissue, through the body into the reproductive tract. But it can leave holes/scars.

Vigilance in group living

Central to any predator's strategy is to minimise the distance between itself and the prey before it is detected. Sociality counteracts due to 'Many Eyes' theory - bigger group the bigger distance predator is located. Anti-predator advantages - as group size increases, individuals can decrease their own vigilance without increasing the risk of failing to detect an attack. However predator counter strategy - pick out and preferentially attack less vigilant individuals. Dilution of risk - 'safety in numbers' - if approached by a predator that can only eat one group member, risk is 1/n - so risk decreases as group size increases - however if detection/probability of predator attack ∝ to group size, this is counteracts - although evidence suggests this isn't usually the case. Prey may synchronise to swarm predators - eg turtles, cicadas, bats. Communal Defence - sperm whales threatened by orcas known to adopt Marguerite formation so injured/vulnerable individuals at centre of formation; larger located outside Musk ox also adopt a group defence - weapons facing outwards

why do starlings sing in the spring based on the 4 questions in biology?

Changes in day length trigger hormonal changes, which trigger singing behaviour. Because they have learned the song from parents/neighbours. Because the song evolved from simpler vocalisations in their ancestors. To attract mates for breeding. These are all correct answers to this vague question.

which prey should predators select?

Choose the most profitable - if there is a choice. Ratio varies with: predator size, prey size, how easy it is to find/abundance. However species don't always choose the optimum - it could be as they don't want to wait for optimal prey so generalise to suboptimal prey. Wait time might determine how choosy they are. Difficult to test these complex behaviours

Copulation attempts by unfavoured males

Choosy females should have preferences for certain males but un-favoured males still want to mate so attempt to coerce/force females to copulate. More likely in species where there is size dimorphism - as if not females will be able to resist). Females may emit distress calls when subordinates attempt to copulate (manipulation) but they may still copulate.

Swarm intelligence

Collective behavior of groups that are capable of devising solutions to problems as they arise, eventually leading to coherent global patterns. Individuals independently acquire information that is combined/processed through social interaction, problem is solved in a way that cannot be implemented by isolated individuals. Individuals are less likely to come to the right decision than a whole group e.g. guessing marbles in a jar. Directional decisions in birds most will be slightly off but the collective is usually correc experiments on pigeons/skylarks. However it may be emergent Sensing of Complex Environments - basic interactions between individuals - those at edge of gradient detect change and info spreads through group

adaptations for aggression

Communication - behavioural - signals and displays - morphological - agonistic signals - ornaments and colouration. Fighting - behavioural - trials of strength (injuries/fatalities - infrequent but do occur) - morphological - weapons and large body size.

Costs of group living

Competition for resources e.g. food in fieldfares - nestlings die primarily from starvation. Increased risk of parasitism/disease e.g. ectoparasitism in cliff swallows. Increased opportunities for reproductive interference/suppression - reproductive interference, brood parasitism, EPC. In some cases, predators may be disproportionately attracted to groups -especially important for predators that use non-visual senses.

The behavioural repertoires of animals.

Comprising of: Innate behaviour - which animal is born able to perform - 'instinctive'. e.g. turtle hatchlings, honeybees dance, finding young 'cute' - simpler behaviours, e.g. primate grasp response are reflexes and genetically determined. Learned behaviour - develops as animal grows and gathers experience. Caveat: There is often no hard and fast distinction between the two. Learning can act to modify species-specific fixed action patterns - most innate behaviors improve with performance as the animals learn to carry them out efficiently.

parent-offspring conflict

Conflict arises between P-O over how much P will invest in O.stemming from the opposing genetic interests of parents and offspring. Offspring demand more resources than their parents are selected to provide. Parents - Offspring a and b are equally related to the parent (r = 0.5) therefore have equal value. Offspring - Values itself (r = 1) twice as much as it values sibling or parent (r = 0.5). game theoretical model - assumptions - that offspring are of equal value. Under selective pressure to demand more food than sibling.

Selective consumption of the brown bear

Consistant with optimal foraging theory. When there is an abundance of salmon they eat the fatty part maximising energy intake as it's less costly to catch new salmon than to eat less fatty parts. Lincoln

Animal Personality

Consistency in an individual's behavioural responses overtime/situations from timid to bold. Boldness - tendency to take risk/investigating novel stimulus. Experiement - fish trained to go through mesh and get food - fake salmon on the other side timid - won't go through, bold - goes through gets food and goes straight back each time. Aggression, activity, exploration, sociability, boldness - also used to describe behavioural type - social/asocial, bold/timid, aggressive/docile. Importance - group-living/sociality, dispersal & migratory tendency, reproductive success, response to environmental perturbation, risk of predation/parasitism, interspecific interactions, competition, habitat use...ubiquitous

Signals of individual quality

Conventional - quality that displays the quality of a male e.g. large claw on fiddler crab. Costly - energetic displays e.g. fiddler crab waving it up/down. They are both costly to the male. Iridescent colouration in butterflies - sunlight reflecting from their scales - as they chose the best spot to warm muscles to fly properly

Prisoner's dilemma

Cooperation is not an ESS in this theory as: Overall, both players do better if they both cooperate, yet each individual player does better if they defect.

parental care

Cost of reproduction normally higher for females due to baseline costs (gamete) greater. Any investment by the parent in an individual offspring that increases their chance of survival (reproductive success) at the cost of the parents ability to invest in other offspring. To produce viable offspring parents often have to contribute more than the cost of gamete production. Putting energy and resource onto offspring that could be used for other things e.g. self maintenance, future offspring

innate recognition of predators

Crucial for animals to be able to recognise danger. Learning requires experience, but experience can be fatal - 1st encounter could be last as requires sympatry in evolutionary time Visual cues used in fish/birds, chemical in fish/amphibians and auditory cues (songbird alarms) in brush turkeys (not visual cues). Most studies find generalised response to certain qualities - relatively labile predator recognition template in early life. Sympatry requirement (predator and prey evolving together) is one reason introduced species such a problem. In general - little eyes/big mouth - predator, big/big - def predator, big eyes/little mouth - not predator

egg mimicry in cuckoos and host coevolution

Cuckoo eggs usually larger than those of the host, but much smaller than would be expected given the size of the cuckoo. There is a high degree of mimicry which is why there are highly different genes for the amount of variation between host species. Most hosts show discrimination against eggs and eject eggs that look too different. The degree of mimicry is related to the host species' ability to discriminate - less discriminate hosts the lower similarity between eggs. High variation between species of different host species.

Hawk-Dove game

D - always display but never fight H - always fight only withdraw when injured. Which one is evolutionary stable depends on the cost/benefits. D will give up when H comes along, with 2 D one will win arbitarily. Pay-off will vary according to opponent. HvsH - 50% chance of winning but 50% chance of injury. HvsD - H always wins, D no injury, no win. DvsD - no injury, 50% chance of winning. Obviously real world not 50:50 but model simplification. Can form a pay-off matrix based on this (pic). - different stratergies will be more beneficial depending on cost/benefit - look at lecture if want - in this instance D wouldn't be evolutionary stable as it could be invaded by H - not stable in real world

ideal free distribution experiments

Davies - swapped at which end got more food and measured how many fish it took some time for them to figure out but then it is fairly close to the model. Parker - male dung flies mating - dependant on female arrival and dung quality. Harper - feeding ducks at different areas - individuals close to model. Quaintenne - overwinter on esturine mudflats. 3 models used - surface distribution (no relation), suitable habitat distribution (65% variation explained) and ideal free (83%) - so 3rd fits.

Predation from the prey's perspective

Dealing with risk. Recognising threat. Trading off risk and reward. Strategies to avoid/overcome risk at each stage of the predation cycle

local mate competition in wasps

Degree of bias in sex ratio should be determined by strength of LMC. Tested in parasitoid wasps - females lay eggs in pupae of flies. Only mated females disperse, sons compete to fertilise daughters. Discrete isolated brood - however sometimes multiple mothers lay in same insect so multiple males are produced

what is the predation sequence?

Detection, capture, attack, consumption. Prey animals may mount defenses at one or more stages in sequence. Avoid detection but if can't, then avoid attack/capture/consumption.

preventing detection against predators: Preventing attack (chemical)

Deterrent used by many small animals e.g. nudibranchs, seasnakes, caterpillars but not many mammals but skunks. Aposematism - signaling poisonousness. Mullerian mimicry - two or more unpalatable species converge to look similar and gain great benefit. Batesian mimicry - edible or palatable species resemble an inedible species - success is frequency-dependent.

Sexual dimorphism

Differences in physical characteristics between males and females of the same species. In primates increases with the number of females per male in the breeding group (Clutton-Brock). Primate species dimorphism depends on the sex ratio of males to females. Where equal no. of male/female the size is not too different - where there's 2/3 females per male - size of male increases - 2x the size

Group structures

Different positions in a group bring different pay-offs - not all members have the same costs and benefits. The safest place to be is often in the centre of the group, out of harm's way but central individuals get less food, so cyclical changing of positions according to motivation Change position as hungry animals move faster as they become sated they slow down - typically simple explanation

Non-fisherian sex ratio

Differential investment returns due to group structure: local mate competition. In species with limited dispersal brothers compete for females. Only a proportion of males offspring will be successful. Unsuccessful sons are a waste. When sons compete their average value to the mother is reduced therefore mothers should favour daughters. Selection should favour demales that don't waste investment. Acarophenax 1 son to 20 daughters (.048). Although need more than limited dispersal to keep skewed dispersal

aposematic colouration in animals

Display warning. To show if eaten predators will become ill - learn not to eat again. Black and yellow stripes are a common warning pattern - it's seen in distantly related species. Mimicking dangerous colouration is sometimes used as making poison/sings are costly but mimic is less so.

Social aggregations

Distinction between this and other forms of animal aggregations. True social aggregations usually involve social attraction. Also, animals in social aggregations must be able to communicate - they need to be in sensory proximity. Experiment on fish determining how much time they spent in these social aggregations Social are not the same as resource-based.

Locusts - social aggregations

Dramatic shift from being almost entirely solitary to being social - transition caused by tickling (paint brush has same effect). Causes massive physiological changes - brain increases in size - start producing pheromone - feeds into behavioural change. Why get locust plagues as once they reach a certain density it completely changes their behviour

Predator adaptations for hunting

Due to a number of hunting strategies can mean they have to specialise - morphological adaptations depending on prey e.g. orcas, tits, bats. Adaptations to prey physical defences e.g. crows drop shells from height, wolf fish crush crabs and lobsters, whelks drill through, mantis shrimps punch through as second leg is heavily modified - different techniques for same prey. Some predators have adapted to chemical defences e.g. grasshopper mice are immune to the venom of many of their prey species

egg rejection rate in cuckoo hosts

Dunnock-cuckoos lay non-mimetic eggs yet dunnocks do not reject - probably due to a short evolutionary host-parasite relationship - whereas highly mimetic eggs will get rejected at higher rate Stoddard - multivariate analysis looking at overlap between morphology. The overlap doesn't seem to affect rejection rate - newer species haven't had time to recognise and cuckoos haven't had time to mimic This is why there's a high no. of species that are parasitised but only 11 common - older ones are harder to parasitise so moved onto new species. Stoddard used fingerprint recognition - pattern analysis of both eggs

preventing detection against predators: Preventing capture (high-contrast markings)

E.g. bars, stripes proposed to serve for "motion dazzle," make difficult for predators to accurately assess speed and direction moving prey. Works opposite way to crypsis where animals conspicuous when they move, but protected when still. As widespread use of striped bodily patterns might suggest role for motion dazzle (only correlational evidence/human experiments) - can't focus when they move. Anecdotal report of stripes on Chionactis occipitalis appearing to move in opposite direction to snake's movement - may exploit peripheral drift illusion - peripheral drift illusion - as its moving forwards pattern makes it look as if its moving back

preventing detection against predators: Preventing capture (misdirection)

E.g. lizards can shed their tail - the autotomised tail wriggles to attract predator allowing escape. Many insects have false heads The insects also perform 180° turns after landing to confuse observing birds. Misdirects attack (as most animals use sneak attack from behind) AND gives predator a surprise when animal moves wrong way. Sea cucumber - eject content of intestines so predator will go for that and they can get away. Eye-spots - development is plastic; occurs in response to predator exposure - functions to increase survival

Pied wagtails - prey choice

Eat flies - most efficiency 7mm (mid-sized) in terms of calories gained. They eat the optimal even when 8mm are the most common. But they did not only take optimal prey - therefore not completely efficient.

Why delay dispersal with cooperative breeding?

Ecological constraints hypotheses is widely accepted. Combines: habitat saturation model, marginal habitat model, benefits of philopatry model. Life-history hypothesis is complementary.

Economics of resource defence

Economic defendability - territorial behaviour should be favoured by natural selection when defence gains more energy than it costs. Cost to holding resources - good resources attracts competitors - the better/more resources the more competition. Benefit slows at a point when e.g. can't eat that amount, travel costs, defence costs and becomes a point where it's too expensive. Lappen - gibbons defending fruits in trees - as territory quality increases, home range decreases - expected. Mayor - beavers vary range of territory size - the average is close to the optimum. Sharing territories (Davies) - wagtail - some species won't abandon large/rich territories but share it with others - help with defence, good quality territories had higher food renewal e.g. big trees dropping insects in the water

where to feed?

Efficient foragers should choose the best place to feed. Animals choose their feeding sites to allow the most profitable feeding trips. Best site may change during life e.g. restricted by SA:body mass ratio in marine iguanas. Often have to investigate proximate mechanisms to answer questions about function - how (e.g. iguana thermal biology) to determine why foraging behaviours differ.

female tactics in mating

Eggs are costly and in limited supply - females should be choosy and mate only with high-quality males - as they should increase offspring's chance of mating - or males who provide parental care. As this maximises offspring survival and subsequent reproduction by female. Female reproductive success is primarily limited by the quality of offspring - sometimes by parental care and internal fertilization may restrict tactics available. If this was completely true to Bateman as according to this females should just mate once but 90% of bird species EPC.

Life-history hypothesis in cooperative breeding

Emphasises role of life-history in the evolution of cooperative breeding. Cooperative breeders viewed as being at the K end of the r-K continuum (trade-off between quantity and quality of offspring). Delayed maturity, high adult survival, small clutch size, low reproductive rate, low dispersal rate. Initial papers found support for hypothesis but more recent studies cast doubt on its validity

Anti-predator advantages of group living - Predator confusion

Encountering a large group of prey can cause sensory overload. Predator success rate typically drops when prey group size increases. Critical element in any predator attack is timing - when confronted by a large group of animals, predators appear to become indecisive and the split-second hesitation allows prey to escape. The confusion effect only works when all members of a group look the same - if 1 stands out it's targeted. E.g. Painted wildebeest (Kruuk), dyed fish (Landeau)

multi-component signals

Enhance: detectability, discriminability (e.g. from other background signals), memorability. Aposematic colouring, taste and smell in ladybird. Sexual displays with sound and vision in red jungle fowl

what is the proposed mechanism for group selection?

Evolution of behaviour that's for the good of the group. Groups comprising unselfish individuals do better than groups of selfish individuals. Less chance of resources being used up, less energy waster in competition, fewer fatalities from fighting. These groups would be less likely to go extinct than selfish ones. It was proposed for behaviours seen that supposedly didn't fit with natural selection

Why do cuckoo hosts accept parasitic eggs?

Evolutionary Equilibrium - acceptance behaviour may be due to the costs of rejection e.g. Accidental damage and ejection - reed warblers occasionally throw out or damage their own eggs as it is difficult pick up/remove egg. Optimal degree of egg recognition ability. Learning involved in egg recognition own and parasite eggs especially as parasitism for individuals is rare. Optimal level - trade off between keeping something that may be parasite and keeping weird egg that could be own e.g. egg blood on parent from ectoparasites when incubation occurs blood got on - if she thinks its a parasite shed be removing own egg but its just markings on her own

Brood parasite-host coevolution

Evolutionary arms race - brood parasites evolve adaptations to maximise success with egg mimicry, rapid chick development. Hosts evolve tactics to avoid parasitism with aggression towards parasites, egg recognition. First unsophisticated and then ramps up for complex strategies

mating systems

Evolve as the degree of reproductive cooperation varies between species. The bond may last for the mating season or longer e.g. life-long Monogamy - stable social pair bond between one male and one female. Polygamy - stable social systems with 'pair' bonds between multiple individuals: Polygyny - one male with multiple females - e.g. male sea lion with hareem of females during a whole breeding season usually mating multiple times during the season. Polyandry - one female with multiple males not common in nature. Polygynandry - mating between multiple males and multiple females - uncommon.

what factors influence fighting?

Experience, size, strength, weapons, energ, ownership, skill. Size was the only factor measured at first then realised it's more complicated. Resource holding potential. Actual chance of winning varies between contests - depends on the ability relative to the opponent

Load size in central place foragers with marginal value theorem

Experimental manipulation with foraging starlings (kacelnik). Beneficial curve was stepped as worms were added. Results matched the theoretical assumption.

Predator adaptations to outsprint/predict prey

Fastest animals on land, (air/underwater) are all predatorse.g. peregrine falcon (390 kmh) (terminal velocity could be higher than this); Eurasian hobby 160 kmh; Black marlin 130kmh; Cheetah 120kmh - great acceleration; Australian tiger beetle (171 BL/s or 1.86m/s) - causes visual processing problems. Where predators are able to predict abundance of prey in time and space, they can forage effectively by congregating there e.g. grizzlies and salmon, orcas and sealions

Cooperation with sharing of blood by vampires

Feed close relatives and unrelated roost mates that fail to find a meal. Donors recognize cheats. Close association in roosts is important. Benefit to recipient greatly outweighs cost to donor. (Wilkinson)

What are the fundamentals of behaviour?

Feeding - need to prey on organisms to survive. Fighting - animals frequently have to fight for limited resources e.g. food, reproduction, territory. Reproduction - the value for fitness, the above are means to produce. Communication - involved in all above

sperm limitation in sex-role reversal

Female fertilisation success constrained by supply of sperm (not by access to males but their gametes). Female reproductive success limited by rate of access to male gametes. Free spawning marine taxa, due to dilution effects (releasing gametes into the environment - less opportunity for choosiness). Copulation involves the transfer of a spermatophore (costly to produce).

maternal effects of predator recognition

Female field crickets exposed to true predator cues eggs prior to being laid - when offspring tested, these were more wary than controls. Survivorship greater in exposed group. Exposing already laid eggs to spider cues made no difference - clearly a maternal effect (Storm)

Parasites and host behaviour: Glyptapanteles & Thyminteina

Female oviposit into caterpillars who continue developing and feeding until parasitoid larvae emerge. Not all larval Glyptapanteles emerge from host. 1-2 remain behind and active to guide caterpillar to the stem of plant and cause it to undergo behavioural changes -stops feeding and moving -more head-swings upon disturbance.

what is the cost of finding unmated males resulting in polygyny?

Females actively choose mates. Females may expend a large amount of time and energy finding an unmated male and often species are time limited e.g. birds, have short breeding seasons and short lives. S females may choose polygny as cost of choosing outways poly if it takes too long

Reproductive tactics

Females and males have different tactics - sexual conflict partially due to anisogamy. Males and females are defined by the size of the gametes they produce - male gametes small, cheap and produced in millions; female gametes large, relatively expensive and fewer in number. The degree of difference differs in species, in humans sperm is 1 millionth size of egg, in extreme cases 1million billion sperm to 1 egg. Microgametic sex - males. Macrogametic - females - energetically demanding so limiting

Pre-copulatory mate guarding in crustaceans

Females can only mate when they moult this happens infrequently (small window of opportunity). Males must guard Females during the pre-mault phase to ensure access to copulation. Males will fight over ownershop to guard females. In Thermosphaeroma thermophilium males provide locomotion - females try to shake males off. Males will try to hide females - limiting food and mates. Male costs - locomotion, predation, food; benefits - mates. Females costs - restircted mate choice, predation, food; benefits - not sure - although males that resist shaking may be high quality. Experiment 1: manipulation of sex-ratios - larger males more successful. Experiment 2: reduced female resistance - intoxicated females spent less time struggling - females attempt to reduce time being gaurded.

sperm competition in damselflies

Females mate with several males and actively promote male-male competition. Males have sperm scoops on their penis removing >90% of previous males' sperm before releasing own gametes. Last male fertilizes most eggs. No pairing - promiscuous - females court to get multiple males to mate this wouldn't be easily explained with bateman

female coping mechanisms to un-favoured males

Females may emit distress calls when subordinates attempt to copulate (manipulation) but they may still copulate. In birds sperm deposited in the cloaca and evert the cloaca ejecting sperm quickly - sometimes before he dismounts. Pizzari - found ejection was more likely with a low ranking male, transplanted males between groups artificially changing social status - when males elevated sperm ejected less. Females don't judge males in an absolute sense but compared to other males

sexy son hypothesis

Females may still benefit from breeding polygynously despite costs of being the second female. May produce sons with greater ability to become polygynous as adults - good genes model. However there is little evidence especially since heritability is too low.

polygyny threshold model

Females should mate polygynously only when the benefits of doing so (extra resources) exceed the costs (sharing resources). When resources are limited females should mate monogamously on high quality territories - until all high quality territories are full. Other options - mate polygynously on high quality territories, mate monogamously on poorer territories. Game theoretical model OR Ideal free distribution - benefit and cost - monogomous beneficial up to a certain point of saturation and then beneficial to be a 2nd female.

what is Bateman Principle?

Females tend to limit male reproductive success more than males limit female reproductive success

why should females seek extra pair copulations?

Fertility insurance - if only mate with 1 male - he might be infertile. Acquisition of nutrients e.g. spermatophores. Parental care - 2 males can care more than 1. Avoidance of harassment Change of partner - if not mated with top male - don't have to accept it. Genetic diversity. Good genes. Sexy sons

when are signals not enough

Fighting more prolonged and dangerous when contestants are closely matched. Contestants can't assess their opponent and make decisions on the basis of signals alone. Weight asymmetry of 0 = same size. If there's a big difference the fight doesn't last long. Dangerous activities are more likely when they're evenly matched

Finding food in groups

Find patches more efficiently in groups via 2 main mechanisms: 1. With more individuals, groups can search an area more effectively - 1 individual finds food, others respond to social cues and arrive at food patch ('local enhancement'), the group acts as a 'supersensor' - sensory capabilities of individuals are summed in a group. 2. The group acts as an 'information centre' and comprises the collective information of group members. Scroungers - social cues for watching individuals tell that a group member has located food/location/quality - 'public information' - can then be used strategically to maximise foraging benefits. Examples - local enhancement in goldfish (Pitcher). Ospreys - pay attention to others and start hunting in the same direction - uninformed up to an hour whereas informed only take ~5-15 mins. Information transfer in evening bats - leaders "produce", followers "scrounge" - followers - don't have to expend energy finding food.

Sticklebacks - prey choice

Fish length compared to prey length experiment - found optimal prey is half buccal cavity length. Ingesting the right size per swallow is half the capacity of the mouth. They seemed to be taking the right prey size in both the wild (examining stomach content) and lab

differential investment returns due to environmental effects: maternal condition

Fitness of 1 sex more affected by a unit of investment e.g. in mammals mothers invest milk into their offpsring. Good maternal condition = more milk and better quality = bigger offspring. Males fight for matings - big males win more fights so fitness of males is tied to maternal condition more than females. So, females in poor condition produce more females - subordinates produce more females. Environment cuasing deviation from equal sex ratio - when 1 sex is more costly. Producing milk is more energetically costly than gestation. However don't know quality of environment when offspring are born so can either abandon offspring or adjust sex ratio. Bigger females are still beneficial but isn't needed.

Experiments on female distribution theory

Food supplements were used to reduce the territory size of female dunnocks, allowing males to monopolise females (Halliwell). Resource distribution mediates social and mating behaviour in a family living lizard. Manipulated resources - by adding could reduce females home range - meant fewer mates that males could monopolise as they are not moving around as much. Increased range - increased mates as cant be monopolised

Anti-predator advantages of group living

Functions can be sorted into categories: Reduce encounter rate with predator - clumping of prey distribution, selfish herd (domain of danger) - trying to put another between you/predator - group size contracts. Reduce success of predator - vigilance, dilution of risk, confusion, predator-predator interference, mobbing/cooperative defense

what is the function of behaviour?

Funtion: the fitness value of a behaviour. How does the behaviour maximise the animal's fitness - relative no. of genes contributing to the next generation? How is the trait adaptive?

P-O conflict current vs. future offspring

Future broods - parents hold back resorses to invest in fiture reproduction. Experiment burying beetle (Ward) - parents with experimentally enlarged broods (increased demand) produced fewer offspring in subsequent breeding attempts. Reproductive success declines in each breeding attempt - females have to balance current with future repruduction

How do snake genes affect dietary behaviour?

Garter snakes from coastal and inland pops feed on different prey. Coastal snakes eat slugs, inland refuse them. Differences persist in lab reared snakes independent of the mothers diet. Showing that it is not a learnt behaviour.

Genotypes in response to novel environments

Genotypes vary in response to experiment, but do not perceive differences in novelty - norm flat, phenotypic plasticity is null - Boldness/exploration identical. Behavioural responses decline with time -phenotypic plasticity - but all genotypes act the same - boldness/exploration are different, but genetically identical - behavioural response diminishes as they get used to the stimuli Genotypes differ in how fast they change response to experiment with experience -exploration/boldness are two different traits.

where to feed for the marine iguana?

Grazes on macroalgae. There is an ontogenic shift in foraging behaviour with age and size as they are ectothermic so need the sun to warm. Can only forage at low tide, get splashed and cold, if low-tide is late then might not warm. Inter-tidal <1.2kg, sub-tidal <1.8, both 1.2-1.8. Sub-tidal forgaing not resticted by tides but smaller animals cool faster so would make smaller trips and they aren't good swimmers so would take longer to reach food. Sub-tidal is more efficient by only for larger.

Lek: predation risk hypothesis

Grouping/displaying exposes males to predation. As chorus/lek size increases the chance that an individual will be predated will decrease - so individual mortality decreases - therefore higher pressure for larger groups. Little empirical evidence, although some papers support this model e.g., Gibson/Ryan with frog species predated on by bat - support for this species but probably not many.

cooperative breeding in the dwarf mongoose

Helpers are prevented from breeding for 3-4 years by a male and a female. Unrelated helpers wait to take over breeding territory. Breeding helpers - older females may be allowed to breed. Pseudopregnant helpers - young females may mate and lactate, but do not give birth.

what are the objections to group seleciton?

Groups must die out at different rates - this is the case for any kind of selection. But extinctions are relatively slow. Individuals die more frequently so natural selection on individuals will be far stronger than group selection on whole species. Whole groups are less likely to become extinct than individuals. Differences between individuals is bigger than the difference between groups - more raw material for natural selection. Unselfish groups would have to be isolated from selfish groups - but barriers between groups/recourses are rare

Predation as a selective force: guppies

Guppies in Trinidad live in streams differ in predator species to contend with. Some stream sections are high-predation environments (HP) others low-predation (LP) - can be adjacent, but separated by natural features. Effects on life history: HP guppies mature earlier/smaller and produce more/smaller offspring (quantity over quality). Affects appearance and behaviour: HP males smaller/drabber than LP males (high-quality males usually bright orange against brown background). HP males invest less in courtship (sneak copulation). HP guppies shoal far more. Transplanting guppies from HP to LP sites (and v.v.) allows exploration of evolution - transition between types happens quickly - few generations. If release fancy guppies (captive) into environment in a few generations they would revert to looking like the wild phenotype.

assumptions - shortcomings of the Hawk/dove model

H/D assumes symmetric contests. With opponent placing the same value on the resource. Opponents with equal resource holding potential. This is not usually the case - real world is more complicated - e.g. individuals differ in fighting ability

Fishers equal investment principle

Half genes from each sex. If there is less of 1 sex they will contribute more offspring per capita individuals investing in the rare sex will be fitter - if this is hereditary alleles for producing rare offspring will increase in frequency - however it won't stay rare for long eventually the ratio will return to .5. Selection favours equal sex ratio - benefit of a certain gene declines as it becomes more frequent e.g. sex ratio. Sex ratio of humans 1.05 males: 1 females - slightly biased in favour of females - females XX, males XY - Y is cheaper to produce

Non-aggressive brood reduction

Hatching asynchrony leads to size hierarchies in the brood. Leads to asymmetries in food allocation leading to Differences in growth rate & fledging weight. Mortality of youngest/smallest offspring. Gives the first eggs a head start compared to the final egg - runt - first to die in unfavourable conditions. Experimental study in blackbirds (Magrath) - may seem counterproductive - one highly likely to die - where food resources are high asynchrony differences isn't too large so synchronised is slightly better BUT when food supply is poor synchronised is bad - almost half success as synchronised die off slowly but asynchrony 1/2 can die off fairly quickly. AND asynchrony still has nearly same success with high resource so overall a better stratergy.

Predators strategy for catching prey

Have 2 main strategies - ambush or pursuit - not just 2 catergories but a continum. Phenotype gives clues as to which. Ambush using trap - predator tends to remain in one place; Predator moves around habitat but relies on prey approaching hiding place; Predator stalks prey and relies on pursuit for last part of chase; Pursuit often over long distance

leaders for group decision making

Have no information initially. Informed individuals can guide the behaviour of the group Examined using mathematical model (Couzin) - only small proportion of informed individuals needed to influence a group - larger groups need smaller proportion of informed individuals to reach a collective decision. as proportion of leaders increases the accuracy improves smaller group need higher proportion of leaders for the same success - as leaders increase accuracy improves, smaller group need higher proportion of leaders

Collective decision making

Have to reconcile local interactions with goal- oriented behaviour proactive & interact with environment to find food/shelter/safety About where/when to go - self- organised groups often extremely effective Principles: individuals interacting, variation - information held by members, random fluctuation, amplification, positive/negative feedback. Ant trail following - can be given simple problem to solve e.g. 2 routes between nest and food ants have to make a choice. Shorter route chosen through pheromones Feedback Pheromone evaporates when route disregarded.

sexual selection for long necks in male giraffes

Heavily armoured skull and vertebrae. Mass in males constantly increases with age with females it stops relative to their body size. Probs not due to getting high food as often feeding on low level acacia shrubs.

Cooperative breeding in the Florida scrub-jay

Helpers provide increased protection from predators and are related to the breeding pair they are a relatively long-lived species, habitat saturation in a rare, specialized habitat.

Enhanced survivorship in cooperative breeding

Helping may increase survivorship until breeding is possible. Benefits of large group size for defending territory, finding food and detecting predators. Helping may be a form of 'rent payment' to avoid expulsion from territory. Survival lower for non-territorial individuals.

kin selection in cooperative breeding

Helping may increase the production of non-descendent kin. Helpers must be closely related to the breeders (and therefore the offspring) e.g. white-fronted bee-eaters. Can help explain helping in 55% of cooperatively breeding birds. Long-tailed Tits - Helpers are closely related to the male breeder and the brood.

Adapting and learning predator cues (training)

Highly flexible animals can be trained other species are dangerous. Transmission can occur v. rapidly at different rates for different sensory modalities. Lake with population of naïve prey stocked with predators - at first no response to cues but through social information, recognition of predator chemical/visual cues E.g. in an experiment put lemon in the water when predators were around and learnt to associate lemon with predators

Reciprocity and conditional cooperation between parents

How males and females effectively provide equal care - act reciprocally with each other - visitation was better predicated if they were altering their visits. Nests who were coordinated were more successful

Eusocial insects - social aggregations

Huge diversity of ants, bees, wasps and termites, many of which are eusocial. Form the most highly organised societies in the animal kingdom. Division of reproductive labour and also often a more intricate caste system. Mostly all sisters - often more related to siblings rather than own offspring - cast system e.g. workers.

risk of predation humans vs minnows

Humans one of the few species that live without significant risk of predation. Pitcher estimated that shoals of minnows never > 2m from predators they have adapted to deal with it - 1 way is to be timid/cautious but carries costs - have to balance risk against rewards

sexual conflict - survival of previous young

Lactational amenhorria prevents female mammals rearing young from re-mating. Lactation is too expensive to become pregnant. In lions if a new male takes over its not in their best interest to wait - infanticide. For females to maximise fitness they re-mate with new males - they even solicit mating. Infanticide is common in mammals (Towers) orca mothers help sons kill juveniles of the females they want to mate with = as it benefits her fitness too

Behavioural syndromes - associated with different environments

Hyper-Aggressive males attack everything, chase females away. Suites of correlated behaviours expressed either within a given behavioural context or between different contexts - behaviour in 1 context can be used to predict behaviour in another. More time you spend hiding- less feeding - both are key for survival. Bolder animals tend to be more aggressive, more active and less social - can use as a predictive framework in many instances. Some behavioural types are better in different situations. Slow/fast pace of life - depending on longevity of life depends on what behavioural types are better.

what is the ideal free models assumptions and predictions?

Ideal - animals have complete information about the distribution of resources. Free - animals can go where they want - no territoriality or fighting. At equilibrium - all animals will have the same intake rate in all patches. NOT about if individuals are better competitors.

Resource Aggregation

If a given resource is clumped in time and space, animals that require that resource will also but these are not true social aggregation e.g. tiger sharks at Hawaii's French Frigate Shoals or fish gathering in eddies

manipulating zones of repulsion

If manipulate the zones it changes group interaction - uncohesive. Size of zones are state and species dependent. Highly social species more tolerance to high packing density. Hungry animals may enact a large zone of repulsion and small/no zone of alignment and cease to act collectively. Fearful animals may enact a small zone of repulsion and large zone of alignment - intensely collective behaviour.

would skewed mating decreases the genetic diversity?

If most females mate with the same male in a few generations should all e.g. have the longest tail so why doesn't this happen? Heritability isn't that high therefore don't get this problem - there are many factors e.g. nutrients, brooding etc. that determine this. Another possibly is the lek paradox - don't really know what happens off leks - a lot of mating happening elsewhere and only really observe the mating happening on the lek e.g. southern elephant seal - polygynous hareem system or lek - a lot happens away from lek out at sea - so observations of the lek will be different from genetics of all offspring (that can't easily observe) - so only seeing small part and the skew from lek Only recently with genetic fingerprinting has become cheap enough for genetic analysis of the populations

reasons for sex-ratio distortion (for females)

If sex ratio is skewed: Limitation on rate most abundant sex can access mates. Could be greater than constrints due to costs of parenthood. In female biased pops could lead to sex-role reversal. Disproportionally high male mortaility due to: Intra-sexual agression, increased risk of predation, sex-ratio distorters - selfish genes transferred exclusively via 1 sex and fatal towards the ohter

Herring - social aggregations

In common with many pelagic schooling fish, herring spend their entire lives in close proximity to conspecifics. The obligate nature of their social behaviour is evidenced by the fact that if isolated they die

Trials of strength

In contests decided by communication or wrestling the key factor is assessment. Serious fights with injuries are rare and only occur when rewards are greater than the cost. Most frequently found when males compete for groups of females or limited chance at mating. Pushing with antlers in deer and antlered flies. Wrestling in frogs and toads. 10% of male mule deer injured each year

Plagiorhynchus - parasite and its life stages

Lay eggs into intestines of birds, eggs are shed in feces, isopod will eat - develop in 60-65 days inside isopod and mature larva alter isopod behaviour making it more likely to be eaten by bird forming the cycle

Harris sparrows signal of dominance

In groups dominants often have morphological badges indicating their status. They aren't costly to produce - so how do they stay honest and evolutionary stable? - they have to back it up, dominant individuals probe so bluffing isn't evolutionary stable Experiment painted males black - didn't make them more dominant as they were harassed too much - bluffing too costly

Parental care duties incl. 2 species

In species with bi-parental care one parent could benefit by diserting - offspring would still recive some care. Extra mating may outway loss of care for 1st brood. Parent left loses fitness e.g. male desterting cichlid fish depends on chance of re-mating. Kentish plover (szekely) - more males than females so females desert and male lose fitness. Don't always desert - in late breeding season, if the clutch is large (loss increases)

Increased reproductive success for helpers

Increase future success as a breeder. Gaining experience. Gaining future helpers. Although there is little empirical data. Florida Scrub Jays: correlation between prior experience and reproductive success - confounded by age.

Why do individuals help in cooperative breeding?

Individuals with delayed dispersal do not have to help at the nest. Nine hypotheses main themes: Kin selection. Enhanced survivorship. Enhanced future probability of breeding. Increased reproductive success.

Producers and scroungers in social hunting

Information transfer suggests cooperative network. Game theory - depends on proportion e.g. if theres too many scroungers the advantage decreases, also depends on resource availability. E.g. Two pigeons produced, 14 scrounged (Giraldeau)

Host countermeasures to parasites: behavioural countermeasures - Self-medicating behaviours

Ingestion/application of substances to kill parasites or discourage them from settling. Olive baboons eat leaves of Balanites aegyptiaca to kill Schistosoma blood flukes. Anecdotal: brown bears apply osha roots (Ligusticum porteri) to fur to repel blood-feeding insects. Some birds incorporate plants with anti-parasitic properties into their nests e.g. sparrows use quinine-rich leaves more frequently when malarial infection rates are high. Mexico city, some birds incorporate cigarette butts into their nests as nicotine kills ectoparasites - no. of butts is negatively correlated with parasite density (Sengupta).

Hawk vs. dove real world scenario and pay-off

Injuries are serious so will have a high fitness cost. And cost of injury is often greater than the benefit of the resource. Therefore D can still be invaded by H but HvsH is more costly so no (mixed) evolutionary stable strategy. Either proportion play H remainder D OR All play D sometimes and H other times - ratio depends on cost/benefit. As the value of the resource. Would be beneficial for them all to be D - but natural selection doesn't work like that

Benefits of philopatry model in cooperative breeding

Intra-populational variation in breeding territory quality. Individuals born in high quality natal territories have intrinsic reasons to remain at home. Benefit to staying rather than a cost to leaving e.g. acorn woodpeckers

what is the criteria for female choice?

Large body size, Bright colouration, Elaborate ornaments as they're signals of male quality. E.g. female peacocks that mate with better males lay more/larger eggs and have offspring with higher growth rates. Female Female widowbirds prefer males with longer tails - high quality of males can afford long tail, causing drag, more energy required - an experiment (Anderson) artificially shorten/elongated male tails which changed female choice

problems for Bateman

It is generally valid but it can't explain many common phenomena e.g: Female solicitation and multiple mating, higher reproductive output for females that EPC, male sperm limitation, monogamy, polyandry, male mate choice, sex role reversal. Some females go out of their way for EPC and can have higher reproductive success. Female collared lizards that EPC have higher fitness (greater hatching success)

Natural selection

It is the differential survival of alternative alleles and how adaptive traits evolve. Genes regulate an individual's nervous system, muscles and morphology, therefore its behaviour. Genes are present in alternative alleles so there will be variation in behaviour. Alleles compete for loci. Alleles survive differently.

differential investment returns due to group structure: local resource competition

LMC as a result of non-dispersing males. In some taxa females show limited dispersal. Non-dispersing females subject to LRC, e.g. food in Galago crassicaudatus and thick tailed bushbaby. Limited no. of females can survive so extra would be a waste.

escalation in siamese fighting fish

Lateral orientation (swimming side-by-side), tail beating, frontal orientation, biting, mouth wrestling (potentially damaging), chasing.

Common cuckoo interspecific parasitism

Lays eggs in nests of over 100 other species - only 11 hosts frequently parasitised. Hosts smaller than cuckoo - so can get rid of nestlings easily. Females lay mimetic eggs so individual females are host specialists as it requires a lot of genetic mutations - so females can only mimic 1 species (specialisation) - genes coding for specific morphology but males are non-discriminate. Female cuckoos stake out host nests. Wait until host clutch initiated (by surveying the area) and wait near nest before laying (as need at least 1 egg already there and for parents to be gone), they remove one host egg and lay one egg - at nest for only 10 seconds - most other species take minutes+ to lay. Hosts are aggressive to adult cuckoos near nest and rejection is more likely if female cuckoo is detected - alarm calls used if detected. Eggs and young have physialigocal/behavioural adaptations: shorter incubation times usually hatch before host eggs then ejects other eggs/hatchlings. Begging calls of cuckoo mimic entire host brood so can get most food. Incubation time is usually affected by size of offspring e.g. hummingbird - no time, starling weeks but cuckoo have very short development time and v. able when hatched so can push other eggs/hatclings out. Females raised by host so can recognise when laying their own - less understood how find new host - poss. when can't find current host and choose another and sometimes successful

Decision making of whether to follow

Leadership is extremely important in animal groups - In many species, e.g. herring, caribou, experienced animals lead the others through habitat or along migration routes. The term 'leadership' implies centralised control /hierarchy - not always the case as group movement relies on 'consensus building' regarding timing and direction - as if group splits, all may lose benefits of group membership. Can sometimes see active recruitment - increase in activity prior to a move Process begins when a single individual attempts to initiate a move - others decide whether to join - based on how many initiator decides whether to continue. Success of leadership to an extent dependent on social status of initiating individual e.g. if more dominant individual leads others are more likely to follow.

Direct/indirect predator learning

Learning what is & what is not a threat can be done through D experience (dangerous) or I - can learn socially by observing response of others to visual (esp.) or chemical cues. Relies on classical conditioning - the response to conspecific alarm (predators) is relatively hardwired e.g. gazelles and lions. Chemical cues allows longer-range learning allowing direct identification of predator known as predator kairomones (chemical substance emitted by an organism and detected by another of a different species, gains advantage) disturbance/alarm cues e.g. some fish species release chemicals when damaged telling others there's something damaging

Lek: hotshot hypothesis

Leks form around the a male. Subordinate males are making the best of a bad job. Cluster around a 'hotshot' male hoping to get an occasional copulation. Location within a lek is therefore important - male a should be at the centre with progressively less dominant furthur out. As females are drawn in by alpha males - if b males group around dominant they have more chance of mating

Parasites and host behaviour: maximise likelihood of transmission - examples

Malaria - Plasmodium manipulates mosquito in three main ways: reduces risky feeding, interferes with blood-drinking, tinkers with chemosensory system of mosquito. Nematomorphs - larvae of Gordian worms are ingested by cricket Worm then grows inside cricket until mature It then needs to get to water by making them thirsty. Cordyceps fungus - ant brainjacker - ensures environment at perfect temp & humidity, height maximises distribution of spores, fungus erupts from head taking up to 3 weeks to grow - can wipe out whole colonies.

Why is anisogamy the basis of sexual conflict?

Male fitness depends on no. of mates and maximise through promiscuity. Females depend on quality of males and maximise through choosiness. Males are usually the limited sex - where fitness depends on limited mates - maximise through promiscuity and competition. Females are the limiting sex - dependant on the quality of mates rather than quantity therefore are choosy. Conflict over: Mate guarding by males (before/after). Copulation attempts by unfavoured males. Duration of copulation. Parental care duties (who provides and how much). Damage to females during fights between males or during mating (intentional/accidental). Survival of previous young. Survival of the male.

Post-copulatory mate guarding in water striders

Male rides on the females. Female is restricted in her choice of mate and pays the cost for locomotion - possibly males are contributing some to locomotion but causes females a 25% increase metabolic rate. Females might shake vigorously to get male off - but costly. Experiment (Watson) individuals marked to track - mating is expensive for females but so is struggling - 200% increase in metabolic rate and can be sustained for 16s before rest is needed. On average single females are mounted 20 times per hour. Female decision should depend on rate of guarding + duration of struggle - if there is a lot of harassment not worth shaking. Cost of carrying one male will stay the same no matter how many males around but cost of struggling will increase with harassment - anything less than 19 grabs per hour makes sense to struggle

sex-role reversal in the Wattled Jacana

Male smaller than females. High rates of egg predation so females compensate by laying multiple clutches with multiple males. Males incubate the clutch (as they can't be left), females compete for and hold territories and compete for males. Males pay higher costs as costs of paternity are high - they provide all the parental care and lose eggs to crocodiles. Females store sperm between mating so no guarentee of paternity over a clutch meaning males may waste time/energy incubating anothers offspring. Up to 70% polyandrous mating system. 70% offspring are other males no clear evidence that males are choosy

Lek: hotspot hypothesis

Males aggregate where they are likely to encounter females e.g. male New Zealand lesser short-tailed bats form singing roosts close to large communal roosts - night widely distributed - night cave entrance acts as funnel. Females have very large foraging ranges but always return to the communal day roosts so are briefly in 1 area. Males are conforming to an ideal free distribution driven by female distribution. The denser the female pop the bigger group of males

Sexual conflict and parental care

Males and females share equal genetic interest in their offspring but in many cases, it would benefit either parent to desert and leave the other parent to pay the costs of care due to conflict between sexes of who provides care and how much - want to reduce their own cost. All four possible outcomes are found: no parental care, female only care, male only care, biparental care

Resource defence polygyny

Males defend a clumped resource that attracts several females e.g. food, territories, breeding sites, etc. Polygyny common in birds typically due to resource defence polygyny. Exclude other males and attract females. Male cichlid collects snail shells. Females lay eggs in the shells. ♂ 12 times larger than ♀ - correlates with reproductive success - large males have up to 100 shells and 30 females at once - defence is difficult.

Female defence polygyny

Males defend groups of females meaning size is important - large males have higher fitness. Common mating system in mammals. e.g. Gorillas, Bighorn sheep, Red deer, Sea lions. Siphonoecetine amphipods (Corophidae) live in cases made of sand & shell fragments - males collect up to 3 females and glue their shells to their own. Montezuma Oropendolas nest colonially it's an anti-predator strategy, the dominant male defends colony, excluding all other males gets 80% of copulations - dominant male shifts if females move the colony - which is how know it is female rather than resource defence.

Lek: Female preference hypothesis

Males form a group to stimulate and attract females - females may not breed unless they have 'shopped around' (checked out multiple male) - so leks facilitate comparisons of many males so females can determine good genes. It might be visual/auditory stimulation - stimulated by many males or might be they won't mate until checked out multiple males - forcing males to aggregate.

Pipe fish sex-role reversal

Males gestate/give birth. Females are larger and transfer eggs into brood pouch and then fertilisation takes place. Male doesn't supply nutrients (like marsupials) but keeps them well ventilated with oxygenated and taxes waste away in their bloodstream. The closer to the equator the shorter the gestation: 9-40 days. Higher cost of reproduciton for males. Females show secondary sexual characteristics lacking in males and females are more active in courtship indicating male choosyness

order of gamete release hypothesis

Males have the first chance to abandon with internal fertilisation. Females have the first chance with external - although gametes are usually released simultaneously.

Lek: kin seleciton

Males on some leks are related. May be important in some species, but on most on leks makes are unrelated. Male Golden-collared manakins lek with relatives (Fusani). Inclusive fitness if a closely related individual mates so displaying together at least means some fitness benefits.

How male care should affect batemans theory

Males should be choosy if they have a high parental investment as female quality is important for rearing offspring. Pair-bonds constrain the number of mates and EPCs per male so there's potential for sexual conflict, as females benefit from paternal care but males benefit from extra-pair. Some species use monogamy - which doesn't fit Batemans theory

in which species does lekking occur?

Mammals ~12 species - ungulates, pinnipeds, bats. Birds ~150 species - waders, grouse, hummingbirds, cotingas, manakins, birds of paradise, kakapo, great bustard. Marine iguana. Similar systems found in fish, amphibians, and insects but only recently referred to as leks. Huge genetic differences between species who lek seem nothing in common apart from females are often widely dispersed

preventing detection against predators: refugia

Many animals avoid detection and/or attack by the use of safe space from predators. Can work well but animals pay opportunity costs. E.g. goby fish and pistol shrimp - live hole together - shrimp creates the hole and the goby looks for predators. Not necessarily hiding can be going to a part of the habitat where predator cannot follow e.g. thinnest branches, cliff, clownfish building ummunity to anemones.

polyandry and male choice

Why do males chose this - low cost to parental care and male bias in sex-ratio. First male paternity in second brood due to sperm storage - so 1st might not mind being left and for 2nd might be a "best of a bad job".

preventing detection against predators: Preventing consumption

Many animals invest heavily in physical defences - some sacrifice mobility & rely on impregnable physical defences. Trade-offs e.g. Locomotion, Diverting finite resources to defence esp. in animals with high risk and short life. Crab/snail -sympatric populations of gastropods thicker shells (more calcium). Others invest in 'internalised' chemical defences e.g. Hagfish fill predators mouth with slime and can be compressed without much organ damage. When attacked, sea hares release 2 chemicals: purple ink and sticky substance - 'opaline'. The ink contains amino acids and is highly attractive. The opaline deactivates the chemical senses of the attacker - drawing in other predators to eat their predator. Thanatosis - play dead - many species e.g. lizards, moulting spiders, opposum - its heart rate drops, body goes floppy, starts drooling, urinates and produces a terrible anal secretion (all the signals of death). Injured fish give off a powerful chemical smell - 'Schreckstoff' attracts other predators increasing handling time - ginving a chance to get away

Communication

Many contexts in which animals use communication and it can either be between species or within a species. Definition: a trait that evolved to transmit information - about the environment, sender - suitability as a mate, fighting ability, warning. Especially group living e.g: Waggle dance signaling the location of a pollen source - shaking abdomen in a figure-of-8: direction/angle in the straight bit of figure of 8, how long waggle is distance. Vervet monkeys varying alarm calls depending on eagle, leopard, snakes

sexual selection and contests

Many male sexualy selected traits are characters that enhance an individuals ability in male-male competition. Large body size, elaborate plumage, complex song. Sometimes natural and sometimes sexual selection for fights

Predator adaptations to detect prey

Many predators have finely honed senses that enable them to locate prey Visual acuity in birds of prey and can see UV. help them catch rodents - owls heads acoustic funnel. Sensitivity of sharks to blood. Ability of snakes to see infra-red. Some hunters specialise at certain times of day when conditions suit their sensory capabilities e.g. reef predators in twilight Cone dominated light-adapted eyes of diurnal prey fish not well suited Crepuscular activity is only 5% of the 24 hour cycle but contains 85% of all hunting. Predators strike upward at silhouettes

Changers in social aggregations

Many species change their degree of sociality as they age, or across different seasons. Many fish species are highly social as juveniles, but become increasingly solitary as they age e.g. crustaceans. Others are social as adults, except during the breeding season when the sexes segregate and (usually) males become briefly solitary

Predators strategy for catching prey: Mixed Predator Strategies

Many species use a mixed pursuit and ambush strategy. Use stealth to minimise distance to their prey followed by explosive speed over remaining distance e.g. lions, trumpetfish get up close to their smaller fish prey by hide behind other fish.

does male parental care lead to sex role reversal?

Many species where males provide parental care aren't role reversed. Level of parental care by males has to be very high to out-balance the costs of gamete production in females.

Why do parents over-produce: offspring facilitation hypothesis

Marginal offspring may assist core siblings to survive &/or reproduce - eusocial workers, sibling cannibalism - when a sibling is more valuable as food than as a gene carrier, it should be eaten. Hamilton's rule Common in insects and amphibians.

Male tactics with breeding

Mate with as many females as possible to fertilize the maximum number of ova. Sperm is cheap and seldom a limiting factor, so males often are less choosy selecting mates.

Do helpers really help?

May increase the production of offspring due to: Increased, or more consistent, supplies of food to young. Increased vigilance and protection from predators. Correlational evidence from Black-backed jackals, white-fronted bee-eaters, red-cockaded woodpeckers, and many others. Helpers may allow breeders to attempt more clutches per season - reduce the breeders' responsibilities to the previous clutch. May increase the life span and lifetime reproductive success of breeders. Experimental removal of helpers in Florida scrub-jay (Alcock)

what are the consequences of natural selection for behaviour?

Mediated through phenotypes - successful genes promote optimal behaviour. Maximises individual fitness. A trait that benefits an individual may be detrimental to others in the pop. Produces efficient predators/foragers/copulation/fighters - not perfect but efficient enough. Phenotypes interact with the environment

cheating with signals foraging

Mimicry and camouflage both by prey and predators e.g. eyespots, crypsis, mimesis (mistaken for other objects ), feigning death.

Deceptive signals

Mimicry signals are deceptive. If signals evolve by sensory exploitation they may be deceptive. But selection should favour recivers that resist being manipulated. In particular when the signal advertises quality of the sender e.g. during courtship or contest. Deception is good for the sender but not for the reciever so puts pressure on the reciever. One measure is to make signals costly

Experiments on Cuckoo-host coevolution

Moksnes placed dummy eggs in nests in species not parasitised and they didn't show any rejection. Host species populations outside the cuckoos range show lower response to parasitic eggs and adult cuckoos - magpies in Spain/Portugal parasitism is common, Soler showed in this range whether natural/artificial, whereas in Iceland where cuckoos aren't magpies ignore as havent evolved counter stratergy - no sympatry

Problems with the Polygyny threshold model

Monogamous females more successful than primary or secondary females of polygynous males so resident pair try to prevent settlement of additional females. According to this model at equilibrium pay-off should be equal (reproductive success should be the same) and reproductive success should be equal in each habitat - but this isn't the case -2nd females are worse off. Males and females try to stop 2nd female.

Cooperative breeding in the Black-backed jackal

Monogamous pairs with 1-3 helpers from previous litters they feed pups and the breeding female and increase the fitness of breeders.

Group living/hunting in sailfish

Morphological adaptations for high speed to feed on sardines. They drive them up to the surface and pin them up there so they can only move sideways - injure a bunch or tap and grab one at a time. As injuries build and probability of capture increases - most injured eaten 1st. The ideal capture number (in terms of time expended) depends on shoal group size. Sailfish group maintain high attack frequency - lead to rapid accumulation of injuries - decrease swimming performance - facilitates prey capture

Parental care patterns in fish

Most fish families show no parental care. Male care common with external fertilisation. Female care more common with internal fertilisation.

natural vs. group selection

N. - individual selection unit, selfish and optimal traits, fast (as individuals die quicker) and strong (more competition), responsible for the majority of traits. G. - group/species selection unit, un-selfish, v. slow and weak, extremely unlikely to select for behaviour - even though it could theoretically happen it doesn't

Selfishness and cooperation

Natural selection may be considered to "design" individuals to behave in their own selfish interests and not for the good of their species or the group in which they live

natural selection and foraging

Natural selection should favour efficient foragers. Optimal foragers should: Maximise energy (nutrient) intake (possibly during certain periods - when they can benefit most from the energy). Minimise fluctuations in energy intake.

Imprinting on eggs with brood parasitism

Naïve hosts must imprint on their own eggs to distinguish characterises and reject foreign eggs. Experienced birds have a recognition template for their own eggs as can't reject parasitic eggs without seeing own eggs. Females with less breeding attempts or earlier in the brood haven't learnt what their eggs look like. More experienced (even later in breeding period) reject rejection is 75% (Moskát)

Ecology with behaviour

Need to understand ecological circumstances to understand adaptations - if want to understand adaptive values need to understand selection pressures. Includes normal biotic and abiotic factors. Usefulness of many traits is frequency dependant (how many others are exhibiting the behaviour). Will determine life-history and trade-offs. Behaviour doesn't happen in isolation - partially phenotype with life history and evolution

How do Drosophila genes affect reproductive behaviour?

Normally mate for 20 mins. A mutagen (radiation/chemical at particular chemical point) causes a genetic mutation. In mutants the sensory receptors develop differently. Stuck male mutants fail to disengage as they don't know when to stop or too many and stop too early - neither are common in nature as not good fitness. 'Coitus interrupts' disengage after only 10 mins. Artificial experiment showing genes can change reproductive behaviour?

what is the problem with 'survival of the fittest?

Not a good phrase. Fitness is a measure of relative genetic contribution to the next generation - not physical fitness! Flipped around - fitness comes after being able to survive - it is a measure of reproduction

Evolutionary Match/Mismatch

Novel Environment/organism All feed into an organisms - past environments, cue-response systems (adaptive traits -fixed action pattern), individual fitness. Evolution shapes individual fitness through a variety of mechanisms e.g. sensory cognitive process (Darwinian algorithms), genetic variation

ownership and resident advantage in contests

O - Male lions compete aggressively for oestrus - among pride members O is respected - if equal in size males with females aren't challenged (following takeover reproductive success is low 1/3000). 1. Residents are better fighters, 2. more to lose, 3. decided aritarily. Experiment with great tit supported 2. and fiddler crab 3. as harder to extract someone from their burrow

competition for resources

Occurs when the demand for resources is greater than the resources available. Competition by exploitation - ideal free model - don't physically fight over resources. Competition by interference (individuals attempting to monopolise resources) - ideal despotic distribution, economics of territorial defence.

Begging behaviour in offspring

Offspring use vocal and visual (holding head/body up with bright beaks) displays to complete for food. Parents allocate resources to chicks which beg at highest intensity. No aggression - using cues for feeding - recourse based Two main theories: parental manipulation by nestlings (Arms race) - are chicks under selective pressure to beg more) OR signalling system - a true signaling system - honest - only individual worth investing in could provide all signals - honest signal of flushing with blood, raising up

Polygyny

One male, several females - most common due to anisogamy. Female defence - males defend females. Resource defence - males defend territories to attract females. Female distribution theory - potential for polygyny depends on female distribution as dispersed females can not be defended.

mate guarding

One partner prevents the other partner from participating in extra-pair copulations. White-fronted Bee-eaters - males increase frequency of mating with partner prior to egg laying and sperm competition. Males spend more time near partner prior to egg laying - mate guarding reduces EPCs ten-fold After egg-laying, males pursue EPCs but the female's too busy incubating.

sexually selected signals

Ornaments e.g. the large plumage in male indian pea fowl advertises male quality to females. Orange beaks in male zebra finch - produced by carotenoids

Intra-specific brood parasitism

Over 200 species of birds - far more common than iner - probs found in more species as its hard to detect - have to monitor every nest and mark them to know which eggs were laid to detect a parasitic egg - most birds lay 1 egg per day so an additional egg would mean parasitism Brood parasitism in coots (females have territories) with 2 stratergies: Females who lack territories (can't reproduce) parasitise territory holders - 'Best of a bad job strategy'. Territorial females parasitise neighbours' nests -benefits without the costs.

What are spermatophores?

Packages of sperm placed for external fertilization with additional nutrients for females. Size increases with male body size - as high cost. Repeated copulations deplete the supply. Size/number matches female quality E.g. cricket, hermit crab, woodlouse. Spiny lobster sperm-limitation: spermatophore increases with female size, clutch size increase with spermatophore size indicating male choosiness.

cooperative breeding in Anemone fish

Pairs defend territories (anemones) and may allow unrelated helpers to assist. Helpers are investing in the long-term takeover of the territory. They are protandrous hermaphrodites (first a male as bigger body size more eggs, so pays to be female later) so if either one of the breeding pair dies, the smaller helper can assume the male role.

Parasite and host behaviour

Parasites influence host appearance and behaviour in a number of ways Sick animals behave differently - side effects/pathology simplest explanation which may/may not benefit the parasite e.g. Crassiphiala trematode infests fish ('black spot disease'). - large no. cause reduction in shoaling, increase likelihood of being eaten by bird Hard to determing where 'indirect' ends and 'direct' begins. Brainjacking and zombification - mechanisms to influence host behaviour - maximise reproductive output and increase likelihood of transmission

Parasites and host behaviour to maximise reproductive output

Parasites use host resources so resource-expensive behaviours by the host may not be in the parasite's interest. So might divert resources to benefit their fitness e.g. sterilisation - physiological/mechanical/incidental, growth - gigantism(long lasting infections). Selection for mechanisms that make more resources available to them • reduce costly/risky behaviour by the host and feed and/or protect parasitic young.

Parasites and host behaviour: maximise likelihood of transmission - trophic transmission - examples

Parasitic flatworm - adult stage releases eggs, excreted by bird - eggs eaten by snail, hatch into larvae - travel to gut, develop into sporocysts which travel to antennae, form brood sacs filled with cercariae which are highly conspicuous to birds - snail spends more time out in the light with pulsating sacs. Thorny-headed worm - adult stage in host intestine - embryos released in faeces, larvae develop and are eaten by crustacean (intermediate host) - host consumed by definitive host as they are more conspicuous - orange spot and lack of avoidance behaviour, lodges in intestinal wall, develops into adult. Toxoplasma gondii - infection changes behaviour of intermediate host through slower reaction times and reckless behaviour - naturally affects rats and cats makes the rats more likely to go near cat scent, more open and less reactive.

sex allocation decisions

Parents can vary the sex ratio of their offspring. Facultative adjustment of sex ratio to fit conditions. Must be based on information - might not be perfect but good enough to make decisions.

Why do parents over-produce: resource tracking hypothesis

Parents lay an 'optimistic' clutch size to capitalise on unpredictably favourable ecological conditions. In bad (most?) years the brood size must be reduced. As laying eggs before peak demand from offspring - don't know what resources will be like in weeks time - if happens to be good year can't lay more - therefore lay optimal clutch size then in a bad year individuals can die off (asynchrony). Brood reduction hypothesis - hatching asynchrony facilitates brood reduction.

Optimal parental investment

Parents usually distribute resources among their offspring, but the optimal allocation for the parents often differs from that of their offspring. Conflict - offspring not genetic copy - cost is a linear function - more investment more cost to parent. Benefit to offspring - initially rapid but reaches a point e.g. cant digest more food (finite amount they can eat). Benefit to parent - about half that as the benefit to offspring as .5 related, and reaches a point where more food won't massively increase offspring survival. Both selected for different amounts of food - asymmetry in what parent and offspring want

Different kinds of animal social aggregations

Part of the reason that it's difficult to provide a universal definition of a social aggregation is that there are so many different kinds. Facultative sociality - associate socially when needed e.g. mating. Obligate sociality - associate socially throughout lives. Many species move along between these over their lives e.g. many fish species e.g. more social as juvenile then become less social. The facultative/obligate continuum isn't the only - animal groups may have stable or dynamic membership - may freely accept outsiders or completely exclude. Restrictions may be based on relatedness (e.g. eusocial insects) but there are exceptions, or may accept outsiders in some contexts, but not in others. E.g. cheetas rarely social but when they are only brothers, damselfish only allow individuals under certain conditions.

framework for novel stressors & HIREC

Past ecological factors - suites of correlated behaviors - response to novel environmental factors Predation risk/food availability/social systems (evolutionary history) - boldness syndrome - novel pedators/foods/habitats/dispersal to novel habitats. Personality can be used to shape conservation

Reproductive behaviour

Patterns of animal behaviour related to the production and care of offspring, including the establishment of mating systems, courtship, sexual behaviour, fertilisation and raising of young. Sxual selection, anisogamy, Batemans principle. Male tactics - extra-pair copulation and sperm competition. Female tactics - female choice, extra-pair copulation

Panglossian Paradigm

Pessimism has been used to describe the pessimistic position that, since this is the best of all possible worlds, it is impossible for anything to get any better.

Collective behaviour

Phenomena result from social interactions among individuals - governed by principle of self-organisation. Behaviour of small components linked to functioning of dynamic group-level properties. Control is decentralised - individuals have no global plan (or even awareness). Feedback between individuals +ve or -ve. Group level patterns/properties EMERGE from local interactions. Individuals in group seem to act in unison - turn together, flow around obstacles, move as one - by adopting simple rules.

Host countermeasures to parasites

Physiological responses - immune, fevers/chills. Behavioural responses - grooming, allogrooming, enlist the help of other species, self-medication. Grasshopper infected with parasitic fungus exhibit a 'behavioural fever' and increase activity and basking. Bumblebees parasitised by conopid flies -larvae hatch inside bee and begin to consume it - some suggestion those infected deliberately seek lower temp. to delay development of parasite

Sex role reversal in polyandry

Polyandry is often correlated with reversed sexual selection. Males provide all parental care and males are choosy. Females are larger and have elaborate secondary sexual characters - females have skewed mating success. Females often have higher fitness than males.

Parental care patterns in mammals

Polygyny is common - female uniparental care in 95% species due to prolonged gestation, mammary glands. Males could protect and feed the female - but they usually maximise fitness by mating with additional females.

Are female ornaments related to their fecundity in sex-role reversal: pipefish experiment?

Positive relationship between the amount of blue colouration and number of eggs produced by females. Possibly blue advertising female quality and male choice. Experiment 1 (Jones): Males preferred females with larger skin folds and body length. Experiment 2 (Berglund): males preferred (sedated) females painted with stripe compared to females painted without. And measured development of skin folds with different no. of females (and males); with 1 females some decrease in skin folds, with 1 female and 3 males significant increase in skin folds, 4 females - some increase/some decrease (not significant) but the dominant female had the biggest and seemed to suppress other females - showing competition between females. Colletively these experiments show role reversal: choosy males (assessment of female orgnaments) and Competition (inhabition of orgnament development)

Hamilton's rule

Predicts when an "altruistic gene" will be favoured by selection. If the cost to the donor is C and the benefit to the recipient is B, then the gene will increase in frequency if: r B > C (if the relatedness and benefit are greater than the cost). Where r is the relatedness of the recipient to the donor. Helping is beneficial up to grandchildren but not with less related individuals

prey-handling time

Prey items aren't 'pre-prepared' - predators have to work to find and get at nutritious parts e.g. shore crabs and muscles - take 3.5 hours to get into shells. Handling time must be less energetic than eating the food.

different types of sex ratio

Primary - at birth - key influences are sex allocation decisions. Secondary - in the population - Key influences are sex allocation decisions and parental care decisions. Operational - those availably for reproduction - key influences sex allocation decisions, parental care decisions and differential mortality and life history

cooperative breeding in the Pied kingfisher

Primary helper is related to the breeding pair. Secondary helper is unrelated and attempts to form bond with breeding female - 48% of secondary males obtained mate this way (Reyer)

Evolution of cooperation

Problem of cheating - the Prisoner's dilemma game. Four main theories for cooperation: Kin selection. By-product benefits. Reciprocity. Enforcement. Manipulation.

Lek mating system

Promiscuous mating system - no pair bond. Theories behind it: hotspot, hotshot, female preference, reduced predation, black hole, kin selection. Aggregations where males defend small display territories - displays are typically very energetically expensive and elaborate. Males provide no parental care so females gain only sperm therefore, an excellent system to examine female mate choice. Stable aggregations of males - males will stay in the same place for years - not defending territory for females but just defending for mating displays. The female might return to mate with the same male - but no bond/no other interaction. Driven purely by female choice - extreme adaptation for males based on this. Only 1 lek species where violence occurs - mostly display - hummingbird males fence with bills - not clear how much damage - might just be a display

Advantages of group living

Protection against predators. Can often forage more effectively vs. on their own - finding food, capturing prey - Increased time budget = more eating Reproductive success - e.g. finding a mate - some sessile marine animals, e.g. barnacles - aggregation enables breeding. Energy/resource conservation e.g. drafting - aerodynamics and hydrodynamics (e.g. pelicans, heat conservation. Access can be gained to novel foraging opportunities by group-living animals. Operates via 2 main mechanisms: Gaining access to defended resources - overcoming the attentions of a territory holder e.g. ravens - 6 juveniles beat 2 adults. Co-operative hunting - allows access to much larger prey - but it's only teamwork if individuals fulfil different roles e.g. lions, chimps & killer whales. Adjustment in each group member's time budget = more foraging. Predator avoidance

Handicap theory

Provides an explanation for evolution of elaborate but honest signals of quality in a mate. If the signal is energetically expensive, it cannot be faked thus providing signal of the males' fitness. E.g. Peacock tail - makes it harder to fly, roaring in red deer wastes energy but advertises fighting ability, stotting in Thompsons gazelle - doesn't get further from predator but signals athletic ability

what are Tinbergens 4 questions in biology?

Proximate (how): Causation and Function. Ultimate (why): Development (learn) and Evolution - where from, what for, how does it improve survival/repoduction?

Tinbergen's Four Questions

Proximate: The cause question (mechanism): Which stimuli elicit the behaviour pattern and what neurobiological, psychological or physiological mechanisms contribute or regulate this behaviour? The development question (ontogeny): How did the behaviour arise during the lifetime of the individual? How does the environment influence the development of this behaviour? Ultimate: The function question (adaptation): Why does behaving in a particular way help the individual survive and reproduce? The evolution question (phylogeny): How did the behaviour evolve over the evolutionary history of the taxon?

preventing detection against predators: Preventing attack (Deimatic)

Pulse of sensory information can be used to startle receivers and induce change in their behaviour. Deimatic displays startle predators causing hesitation (bluff) e.g. eye spots on butterfly wings (eye and face-like patterns prevent attack) - hesitation long enough for escape. Experiments suggest - conspicuousness (=high contrast) is essential rather than realism. Has to be 'surprising'. Behavioural change and warning colouration can be combined, as in certain species of amphibians. Deimatic displays can be non-visual e.g. auditory - some animals produce 'distress calls' e.g. peacock butterflies produce hissing sounds and high-intensity ultrasonic clicks causing predatory rodents to flee

preventing detection against predators: Preventing capture (locomotion)

Rapid as prey animals adapted to move fast Experiment on lepidopterans - fast flying species more likely to survive attack - but trade-off - fastest flying insects may have to devote up to half body mass for flight muscle - reproductive cost. Accurate - encoding a spatial map - prey often have excellent local navigational abilities e.g. elephant shrew/sengi follow a certain path. One reason that translocated animals often display stress in a novel environment - stripped of a major defence. Unpredictable - protean behaviour - prevents predator from predicting direction that prey animal will take (erraticness increases likelihood of escape). Frequency distributions of escape trajectories of insects - perfect randomness would lead to perfect unpredictability but vertebrates often peak at 120° - keep predator in visual field (Domenici). A rapid exit can be achieved by either sudden move or surprising (often better) e.g. flying fish escape the water, lizard - run across water, pebble toad fall down hills by tensing muscles.

Responses to stimuli

Reflex response - peripheral nervous system. Nociceptors - sensory neurons that detect damage or potential damage to the body - triggering response of motor neurones. Learnt - learn what will cause harm. Evolution - if haven't then would be more susceptible to harm and therefore fitness decrease.

Inclusive fitness

Relative number of genes contributed to the next generation. Individuals share genes with close relatives. Total genetic contribution includes the genes contributed directly plus the shared genes contributed by relatives. Through direct fitness (reproduction), Indirect fitness (aiding survival and reproduction of non-descendant kin) Inclusive fitness = Direct fitness + Indirect fitness.

Predators strategy for catching prey: Pursuit

Relies on speed and/or endurance or over distance e.g. wolves, hunting dogs. Sometimes referred to as persistence hunting Very effective but the trade-off here is aerobic muscle isn't good for fighting e.g. wild dogs capture rate much better than most predators - but often lose their kills to bulkier carnivores. Follow a trail, picking up prey cues - usually through sight or smell of prey e.g. European catfish follow fish prey by tracking their mechanical wake shed during swimming - can follow up to 10s old & 55 BL (also harbor seals when hunting at depth).

Predators strategy for catching prey: ambush

Relies on stealth, crypsis and limited movement. Not just visual crypsis - predators can change the way they smell e.g. rolling in smelly substances. E.g. assassin bugs - disguised visually and chemically - use prey debris & sticky plant resin Success depends on patience and timing. Trap builders e.g. Ant lions dig pits - as prey try to escape it keeps shoveling sand so it cant get out the hole; spiders webs - work using glue and -ve electric charge as flying insects pick up +ve electrostatic charge with tensile strength and extensible and built in toxins. Some ambush specialists can actively lure their victims toward them e.g. angler fish have fleshy, sometimes bioluminescent growths on forehead then create suction pulling prey in and alligator snapping turtle's tongue looks like worm. Mimics - e.g. fireflies attract mates using light flashes - Photuris firefly mimics females of other species and eats arriving males. Margay mimics calls of tamarins then eats them. Manipulation e.g. tentacled snakes use feint attacks to manipulate escape responses of fish prey - initiates fake attack with middle of body eliciting escape response in wrong direction directly toward snake's (in 1millisecond). Drawing attention to attract prey - Stoats are very obvious so prey don't think they'll attack and get closer, then starts going crazy and then pounce

How do you test for lek hypotheses?

Remove most attractive male. Hotspot prediction: males reshuffle to fill prime position - doesn't make too much of a difference. Hotshot prediction: subordinate males gather around b male or disperse to another lek. Great Snipe: remove dominant = subordinates abandon; remove subordinate (control to make sure it's not a disturbance effect) = subordinates rearrange around dominant male - supports hotshot hypothesis. Is there variation: black grouse - most successful lek territory varies year to year - dominant male determines location - neighboring males have increased success due to proximity to a male - supporting hotshot. Are leks formed in areas where females are concentrated - not in blue-crowned manakins. Lack of spatial correlation between territories of males and females contradicts hotspot hypothesis (Duraes). Deutsch tested if females are more attrackted to larger leks - didn't find in Uganda kob -contradicts female preference hypothesis. Harrassement - Topi (Bro-Jørgensen) females are chased most when on leks contradicts black hole hypothesis opposite to fallow deer. Ruff species supports 3 hypotheses: Hotspot - located near ponds; hotshot - subordinates close to a male have higher fitness; female preference - females prefer males on larger leks (Widemo). So not just 1 single model to explain Lek behaviour.

Iterated prisoner's dilemma

Repeated encounters allow for the evolution of cooperation through reciprocity (mutual exchange). Cooperate on the first iteration; after that, do what your opponent did on the previous move. Successful strategies were all "nice", "retaliating", "forgiving" and "non-envious". Start cooperatively, punish defection, cooperate if the opponent starts to cooperate & do not try to outscore the opponent. Reciprocity examples - For stability, the probability of two individuals meeting again must be high, models predict reciprocity in small groups with individual recognition - e.g. alliances in primates and food sharing.

Parental care patterns in birds

Reproductive success is limited by rate of food delivery to young and breeding birds expend up to 7*BMR (baseline is 1BMR). Loss of 1 parent usually results in brood failure - they split parental care 50:50. They work at the limit of what is physiologically possible to raise offspring - not possibly for 1 parent. Dunnock - variable mating system with monogamy, polygyny (male helps 2 females - spends more time with diminant) and polyandry (2 male care at 1 nest - the more time he spends with female pre-laying e.g. if spent 70% then would care 70%).

when can sex role reversal occur?

Reproductive success of females limited by the rate at which they can access males/male gametes. Possible when: males invest heavily in parental care, sex-ratio is skewed in favour of females, there is sperm-limitation - sperm would still be cheap but there might be limitation or added costs on production.

Non-lethal sibling aggression

Requirements: resources which are limited & monopolizable, asymmetry in offspring, non-lethal, but still violent - can lead to the death of the smallest offspring e.g. Piglets fighting for access to teats - have precocial development of canine teeth (modified teeth sticking out so move head side-to-side) and establish hierarchy within hours of birth. Doesn't directly cause death - degree of aggression limited by recourses. Occationally mothers will produce more offspring than teats - causing more rivalry - bigger ones will push out smaller

preventing detection against predators: masquerade

Resembling inedible objects or pretending to be a different animal e.g. ant-mimic spiders and spider-mimic flies. Not trying to blend in but trying to look like something else e.g. caterpillar-bird poo, caterpillar-snake, fly-jumping spider, fly with spider markings on wing-tips

Why do parents over-produce?

Resource tracking hypothesis. Replacement offspring hypothesis. Offspring facilitation hypothesis. These hypotheses are not mutually exclusive

Contest behaviour

Resourses aren't unlimited. Interactions where an individual excludes an opponent from a resource. Agnostic, aggressive or fighting. Intraspecific - most competition occurs between members of the same species - as they tightly coincide with resource requirements.

Foraging

Responsible for many types of relationships between organisms - predator/prey, plant/grazers. May be simple or complex. Grazers are a form of predation, most cases plants aren't growing to provide food - stealing energy

starlings and sparrows - social aggregations

Restricted but in some cases, newcomers have to join the bottom of the pecking order.

Enforcement in cooperation

Reward cooperators and/or punish cheats. Enforcement alters the costs and benefits of cooperation and can favour selection for cooperation. Can be illustrated by adding enforcement into the Prisoner's Dilemma game. Cleaner wrasse - client fish punish cleaners who feed on them, rather than their parasites, by chasing them or fleeing away. Cleaners are more likely to feed on parasites, and less likely to feed on their clients after they have been punished but transient species that just move through they might only take good bits (cheat)

Trading off risks and rewards

Risk affects animals' decisions in lots of contexts. From foraging/courting under risk, to parental investment - if live in an environemtn with higher predation will invest less and focus on survival.

Contests settled by signals

Ritualised, repetitive, multiple signals, escalate in intensity. Agonistic signals - individuals save time and energy and reduce the potential for injury - still costly. Revealing fighting ability to the receiver - will most likely be too costly to bluff if escalated to a fight

Variable strength of local mate competition

Selection should favour mothers who can cope with this. More than 1 female can lay eggs in the host. With increasing mothers strength of LMC declines. Female bias in sex ratio should diminish with increasing no. of mothers. Successive mothers produce increasing no. of males, also varies with clutch size of each mother - small clutches male biased (>.5) large female biased (>.5)

what does all communication have in common?

Sender, signal, receiver. Information carriers - a trait that has evolved to transmit information.

Which organisms really don't fit into fisharian sex model?

Sequential hermaphrodites e.g. Ballan wrasse change from female to male from 4 years. More than 2 sexes - 2 trypes of male in harvester ant - the queen has to mate with both

what is the rational of group selection?

Setting disputes by communication. If individuals act selfishly the pop would waste energy on competition, over-exploit recourses or dangerous competition. Evolution must produce adaptations that benefit the group. Natural selection cannot produce for the good of the species behaviour - so this is proposed as an alternative. Parents dying to ensure survival of young. Communication instead of fighting. Helping - altruism.

Sexual conflict - male survival

Sexual cannibalism common in arthropods e.g. praying mantis and orb web spiders. Likely when female is larger and when they are predatory. Sperm is on specialised mouth parts which during copulation is ripped off - so he can't mate more than 2. Doesn't run away as his body contains nutrients benefitting his offspring

Indirect male-male competition

Sexually selected traits can evolve for this e.g. sperm competition, as females often mate with more than one male. Not all sperm are equal and copulation doesn't guarantee fertilisation - rivalry through speed, strength, rivalry.

search path in the painted turtles

Short scale movements are more patterned. Long scale are straighter - use these to get to new rivers where they are more exposed to predators. However no evidence for a significant pattern - still not well understood. Straight lines may be the default search path

generalist vs. specialist prey choice

Should eat less profitable prey if - Predators can specialise or generalise. The decision depends on the cost of specialising. The switch to generalising is sudden. Great tit - convayer belt varying the size of worms - if there were more big the tit would specialise, if they were more infrequent - generalise. The change wasn't immediate - but this was most likely a decision making lag - therefore this experiment a good support for the model.

Facultative siblicide

Siblicide sometimes occurs e.g. Galapagos fur seals - up to 23% of females give birth whilst still feeding an older pup -youngest pup may starve or be killed by older sibling during unfavourable environmental conditions - may take weeks. If resources plentiful then both will survive if not younger killed - often slow death. Huge asymmetry in age and size - months older Also found in egrets, herons, blue-footed boobies, owls, kittiwakes, etc.

Family conflicts

Sibling rivalry (non/lethal), P-O conflict, Parents over-producing - resource tracking, replacement offspring and offspring facilitation. Non-lethal can still lead to death e.g. starvation but no 'direct attcks'

Costly signals guaranteeing honesty

Signals are costly to perform/maintain. Negative impacts on correlates of fitness - handicaps the sender. But this is outbalanced by the positive outcome of communication. Only high quality individuals can afford the costs. E.g. zebra finch - carotenoid - if can get enough in diet to make a brighter colour as could mean more cellular damage occurs as not protecting cells in metabolism - but getting more fitness as getting to reproduce (Zahavi, 1975)

ideal free distribution

Simple model of exploitation - animals compete by using up resources - game theoretical model. No fighting for territory - competition in terms of if 1 individual gets the resource the other can't have it. The best possible strategy for 1 individual depends not only on environment but on other individuals. Patch choice model - patch quality (changes from 1 area to the next) and competitors (how many in each area - changes based on no. of competitors). 1st settler should go to the best site - as the individuals increase there becomes a point where the 'best' site is too competitive compared to the 'worse' sites

A model of prey selection

Simplifying: Predators encounter 2 prey types - big/small. Mathematically often have to make assumptions e.g. only 2 prey phenotypes e.g. small/big. Determining cost as handling time and benefit as energy gained. Should only eat sub-optimal prey if the profit from eating > profit from rejection and more searching.

Contests in red deer

Single sex groups until rut in October. Male antlers grow (big investment) during the summer and are shed in Feb. Males compete for and guard harems of females. However even if the dominant male might not have exclusive access e.g. sneaky copulation. Structure: Roaring - rate varies (agonistic - pitch deeper with dominance), tiring; parallel walking - measure of size; antler pushing - strength. Risk escalates between phases - higher risk of injury. 25% injure, only 6% injured at 1 time. Study on 50 fights - 3/4 started with roaring, 1/2 then went to parallel walking, and 1/2 fought

Social system diversity in Cooperative breeding

Solitary to colonial breeders. Singular breeding to plural breeding. Singular - one breeding female per group. Plural - two or more breeding females per group, with either separate or joint nests. Helpers of either sex. Helpers related or unrelated to breeders. Mating system Monogamous, polyandrous, polygynous, and polygynandrous.

Parasites and host behaviour: maximise likelihood of transmission

Some parasites have complex life histories - moving into different hosts. Some parasites have free-living stages that seek out the definite host e.g. those that enter straight through skin at follicle and ectoparasites like mosquitoes. Some manipulate the actions of their hosts to get to where they need to be and others rely on trophic (eaten) transmission.

monogamy

Sometimes it pays both male and female to mate monogamously - social monogamy does not mean genetic monogamy. It's often important for parental care EPC is fairly common. Oyster catchers (van de Pol)- 12 year monogamy (pretty much lifespan) - adter 6 years substantial decrease - most likely be old age. Long term relationship increases breeding success for both

Evolutionary arms race between male and female crickets

Spermatophylax low nutritional value but inhibits female remating. Stong affect on closely related species. Males exploit a pre-existing preference. Female preferences change to avoid exploitation decreasing susceptibility for cheap gifts.

what are sex-roles?

Stratergies for (1) mate choice and (2) competition over access to mates that males and females adopt. Females choosy, males compete. Higher baseline-costs for females. Sexual selection stronger in males.

evolutionary goal of all organisms

Success at foraging and avoiding predation are of no consequence if individuals don't pass on their genes - typically via reproduction. Fitness is a relative measure - must pass on more gene copies than others - not just reproduction but relative to others in the pop and no. of individuals that survive to adulthood.

Enhanced future probability of breeding in cooperative breeding

Territorial inheritance - helpers may inherit territory from breeders or may be able to bud-off a section of territory. Coalition formation - larger groups better able to retain territory, increasing fitness of all group members. Future mate acquisition - if mates are in short supply, secondary males may be waiting to become primary males.

Host countermeasures to parasites: behavioural countermeasures - enlisting other species

That they cannot remove themselves - may be specialised parasite removers or generalist foragers than happen to prey on parasites. Non-specialist: 'Anting' by 200+ species of bird - move over their feathers, removing parasites - some species also crush ants and anoint themselves with formic acid (self-medication). Specialist: smaller cleaner fish remove parasites etc from larger, including predators - mutualism: both parties benefit from cooperating - evolved many times in different fish/prawn families. Specialist: cleaner wrasse experiment -long known but only recently quantified client fish held in cages, with/without cleaners - fewer parasites with cleaners - wrasse occasionally cheat but overall benefit clients (Grutter). Specialist oxpeckers experiment (Weeks) -remove ectoparasites from various ungulates and drink blood/prevent wounds from healing - does this help? - excluding/allowing oxpeckers had no effect on parasite levels - client's wounds took longer to heal when oxpeckers were present.

Optimal group size

The benefits of size eventually plateau as there is an optimum. Unless groups of optimal size can exclude newcomers, groups in nature will be larger than the optimum - as it pays loners to join groups - therefore hard to stay at the optimum. E.g. group hunting in wild dogs - larger packs kill larger prey, have higher capture success, and travel shorter distances in a hunt but have to share kills therefore theres an optimum compared to kg of kill and memebers. Caraco study on lions predicts optimum of 2, so even though 4 lions have lower food intake than 1, lion groups usually larger than this as tt fails to account for complexity of species. Determining group size fitness function is difficult - optimum is context-dependent and dynamic - changes in time/space. Fails to account for inter-individual differences both state-dependence and dominance. Mostly involves free-entry groups.

Ideal Despotic Distribution

The distribution of individuals in space where those that arrive first, or have dominant/aggressive take the highest quality territories excluding others. Still assuming individuals know about distribution of patches, but they aren't free to move where they want and there's competition. Doesn't assume all habitats are the same or all individuals get the same out of it. Predicts a hierarchical distribution - the quality of each individual's territory reflects their rank. Church - fish of different sizes showing the proportion of time spent in open habitat - small spent more time as pushed out of good quality habitats

Kin selection

The process by which characteristics are favoured due to their beneficial effects on the survival of close relatives. Benefit for offspring and non-descendant kin through parental care, feeding siblings, defence of family territory. Sterile workers may help.

The basics of Behavioural ecology

The study of how animals interact with their environment, and the 'survival value' of behaviours. Assumption is that an animal's behaviour is adapted to its environment. Focussed on the costs and benefits of a given behaviour - the so-called economics approach. A central tenet in behavioural ecology is that any given behaviour is ultimately beneficial - otherwise it would be eradicated

Behavioural ecology

The study of how behavioural traits maximise fitness. Key concepts: function, fitness, adaptation, natural selection

Collective decisions - quorum rule

They apply a simple decision rule, called a 'quorum rule' - only follow when a threshold number of leaders has been exceeded - they don't typically follow single individuals. Ward - single focal fish followed a single replica leader on 18 of 20 occasions - but groups of 8 only followed with 2 leaders. Quorum rule reduces the probability of errors being amplified throughout a group. 450 sheep jump to their deaths in Turkey - 1st 1 sheep jumped then 1,500 others followed - sometimes the rule fails

economics of prey choice in shore crabs

They choose intermediate size and are highly selective. Might expect them to take the biggest ones and ignored (largely) very large/small. In wild could put it down to abundance but in a measured lab experiment they replaced each mussel taken. They are the optimal trade-off between energy content and handling time. Measured energy intake with muscle size - small are easier to crack open as shells are weaker - optimum is 3cm crabs usually chose 2.5cm

HIREC - species that are responding adaptively

Timing life-history events (climate change). Shift in call/song frequency (noise pollution) e.g. frogs changing calling patterns due to air traffic. Recognition of new food sources (ecological traps). Respond to new predators (exotic species). Pests - lionfish invasive range - nothing that eats them - prey don't recognise them as predators - pop growing rapidly - decimating local fish populations - reproduce in high numbers so fishermen paid to kill them. Cane toads (large) - itroduced to control pest eating crops from S./central America - nothing eats them as poison glands - they eat they die - sausages laced with a nausea-inducing chemical deter carnivorous marsupials from eating them - teach offspring not to eat cane toad

Trading off risks and rewards - frog and cricket example

Tungara frog variable courtship call. If lots of competition, male can scale up call to make it more attractive with 'chucks' but this makes them more vulnerable to predation. Trachops bat can more easily localize frogs with whine+chuck call so males balance need to attract females with need to stay alive. Male bush crickets have a similar dilemma - top of vegetation is best for song, but worse for predation

Undermatching of the ideal free model

Usually experiments find too few predators in the good habitats Due to interference and depletion. Increasing competitor density reduces intake rate due to food depletion and interference (fighting, stealing food, disturbing prey, territorial defence) so ideal free is violated if interference is common, when depletion is more important than interference the ideal free gives a good fit. The more individuals the worse the model becomes and should switch to an ideal despotic

Cooperative Hunting Game or The Prisoners' Delight

Two players who share food equally. Solo hunter will be mildly successful (4 units of energy), so each gets 2 units. Hunting costs 1 unit, so net pay-off to hunter is 2-1 = 1 unit. Synergistic benefit of mutual hunting generates higher pay-off (10 units). Both individuals get 5-1 = 4 units. (Davies). As get larger prey cooperatively. Hunting is an ESS (4 > 2 > 1 > 0), so they both hunt cooperatively.

Damage to females during fights between males

Unintentional damage may occur when males fight for ownership e.g. female dung-flies/ducks can be drowned. North american garter snakes (shine) - females killed in communal dens, males attempt to mate with sexually immature females - avoid by waking up from hibernation early (other costs). South American fur seals - Males sexually mature at 4-5 but mating dominated by 7-9. 4-5 young grouped males who drag female off but then fight over her. Mature males may try to mate with sexually immature females (yearlings) and crush them

what is Social polyandry?

Up to 7 male Eclectus parrots form a stable pair-bond with one female and help raise one or two offspring. Typically only one male is the father of the chicks in any one year - males mate extensively with female and don't know paretnage of offspring. Operational sex ratio is skewed by female mortality and scarcity of nest holes. Either they mate and don't know if father or don't mate at all

How do shrimp communicate pre sex?

Use chemical signals before copulation. Study injected fluorescence into their digestive system (urinate out of their mouths). Important part of their mating

What is game theory?

Use of mathematical models to represent complex decision making in which the actions of other group members must be taken into account. Success of an individual in the "multiplayer game" depends not only on his or her own strategy but also on the strategies and decisions of the other "players". The most successful strategies result in greater fitness and will be favored by natural selection. Frequency dependence - depends on opponents strategy

nuptial gifts

Used to attract mates and convince them to copulate - large pouch of sperm in protein shell - inducing females to mate. Honest signals of male quality. Female gets resources - females in poor condition will eat it (protein and fats), females in good condition will use it to fertilise eggs (what males intend) Katydids often eat the spermatophore - healthy females incorporate the protein into eggs; weak ones use it to increase their health. Male sacrifice in redback spiders - males summersault into female's chelicerae to induce feeding - well-fed females are less likely to re-mate. Males have little chance of finding another mate so have nothing to lose. The male soma increases the size of egg mass.

Selfish gene

What is important is survival of the individual's genes, not survival of the fittest individual or what is 'good for the species'. However in some cases it looks as if animals are acting for the species e.g. salmon migrate back to spawning grounds using all of their energy and dieing after spawning - which doesn't seem beneficial for the individual which is why some came up with group selection

Manipulation in cooperation

What looks like cooperation on the part of the donor may have evolved through manipulation by the recipient. Inter- and intra-specific brood parasitism e.g. Cuckoos. Some pollination systems e.g. Bee orchids - land on pad and thinks its a reproductive partner so they spread pollen without getting anything in return. Some seed dispersal systems e.g. Burdock fruits.

scramble competition promiscuity

When females are widely scattered, males compete to find and mate first with females. Horseshoe crabs mate in explosive breeding assemblages on a few nights each year - males in good condition arrive attached to females and males in poor condition act as satellites. Male influence: benefit if a female does not mate - may use strategies to maximise reproductive success nuptial gifts can influence female behaviour. Hanging flies (prey size), Katydids (spermatophore size), sperm competition is very important

Local mate competition

When offspring are isolated there are other parents to take advantage by producing sons. Pops sex ratio is irrelevant. In species that produce isolated broods LMC can maintain skewed sex ratios. Acarophenax produce live young, broods are very isolated - inbreeding occurs son fertilise their sisters inside the mother before birth. So no chance of competition between males. Common in mites - pyemotes barbara - male fertilises outside the mother - still strong sex bias but as there's a chance of another male it's less skewed than above.

Evolution of signals: sensory exploitation

When there is a conflict of interests. Assumes senders manipulate receivers. By exploitation of pre-existing sensory bias. E.g. Male spiders stimulate prey sensing receptors in females (will vibrate web/wait for prey) to sneak copulate; lure in angler fish exploits predatory behaviour in prey

Foraging and predator avoidance in black and sand gobies

When they're fed they avoid predators more and less foraging occurs when predator is present. Black goby even less so possibly because they are more conspicuous. Another experiment in real time 3 variations: fed no predator, fed with predator and starved with predator. SWP was low but higher than FWP and FNP was high. When the predator scent was removed both WP dramatically increased.

Certainty of paternity hypothesis

With internal fertilisation the male is unsure of paternity so is less willing to invest in parental care. With external fertilization males have more confidence in paternity but EPC is still possible. So the sex that is more certain of paternity - more likely to give more parental care - if unsure less likely to invest as don't want to risk wasting. Females are usually certain but males with internal fertilisation uncertain e.g. sperm competition pretty common and females usually EPC so males so under weak selection to care. With external - females release eggs and males release sperm they can have high probability that the eggs are theirs. Experiment (Neff) with male bluegill sunfish who perform less egg defense if another male was present when the eggs were fertilised - as more males present less sure of paternity.

Promiscuity

Without pair bond. Brief encounters between individuals - with single or multiple matings. Anisogamy is likely to drive - males are often indiscriminate and females should still be choosy for good genes, sexy son hypothesis, sexually transmitted diseases.

sex-role reversal due to a sex-ratio distorter

Wolbachia bacterium - infects 80% of Acaea encedon butterfly females kills all male embryos. Pop is up to 95% female. This pathogen infects insects broadly - could lead to SRR. Females swarm around plants (non-food) possibly lek behaviour but couldn't be sure without experiment. Captured butterflies and mated (marked them) in a lab and released all (mated and unmated) into a swarm - a higher proportion of mated females left the swarm - indicating they left when mated - female competition. Male choosiness - males more likely to mate with uninfected females - would pay as sons have higher reproductive success

Scramble competition - offspring conflict

Young compete for a position close to the parent. Position in nest is an important determinant of who gets fed. Offspring size important determinant of ability to monopolise primary location - larger/more able/competent - will be able to get more food as block out smaller siblings. Jockey for position where parents will most likely come from - largest in the best position. Determined by environmental conditions - if 1st is fed enough will let others feed. If not enough recourses smaller will eventually have less energy to compete and not get fed. Non-aggressive (as much) form of competition not aimed at killing sibling (but could happen) aimed at getting as much food as poss.

Behaviours often have a trigger

e.g. fixed action patterns occur in response to a sign stimulus or releaser Sign stimulus - releasing mechanism - fixed action pattern Sign stimulus is critical portion of an overall stimulus (or releaser). Releasing mechanism is a neural pathway. Fixed action pattern is the behavioural response Examples: Sexual attraction in sticklebacks: Tinbergen experiment different male shape/colour determine what females respond to - found respond to red underside (not whole male/shape) - male's red belly is the sign stimulus. Egg-retrieving behaviour in geese (Hickman) -sight of displaced egg triggers retrieval behaviour in many bird species but can be triggered by a variety of objects - even if it was seen placed

optimality of patch residence time

if hunting/foraging in a patch need to determine how long should stay before moving to another area. Fitness is related to growth and survival, currency = the net rate of energy intake. Determined by factors: travel time and diminishing returns Extremes are: eat 1 mouthful per patch and then move (costly) or eat everything and move - diminishing returns. Energy gained from stating at a patch gradually tails off. With long travel time should have long patch residence; with short travel time its going to be steeper slope - so shorter time in the patch is optimal