BIOL 278 Exam 2

Sea Turtles - Varying Magnetic Addresses and Finding Specific Locations

Juvenile turtles take up residence in coastal feeding grounds. Each turtle establishes its own individual feeding are and will return to it if it is displaced. To test if turtles can find specific locations, created a larger magnetic coil system. Captured juveniles from the reef in melbourne beach and tethered them up. Imitated magnetic address of Jekyll Island in Georgia (moved south) and of Tavernier Key in south Florida (moved north). So, juvenile turtles have a GPS that assists them in navigating to specific locations. IN other words, they have the basics of a magnetic map. They learned the address of their feeding areas, and when displaced, set their course for home

Sea Turtles - Testing Magnetic Inclination Changes

Kept the turtles in their Florida environment, and varied just the inclination angle. At a 60º isocline, the turtles as a group traveled SW. At a 30º isocline, turtles as a group traveled NE. Isocline was the only thing that changed. Both of these directions make sense to keep them out of the southern or northern atlantic and within the gyre. The hatchlings can distinguish between different angles and respond to them in ways that make sense

EXPERIMENT - Foraging in Grey Mouse Lemurs

Lemurs are small primates from the island of Madagascar. This species is almost entirely nocturnal and feeds mostly on fruit and insects, has huge ears and huge eyes. Really good at gathering light and seeing in low light. It is good at finding its food sources because it uses multiple sensory systems at once. 1. Trained the lemurs t remove a plastic lid from a bowl in order to get a mealworm 2. Choice experiment in which the lemurs had to identify which of two bowls the mealworm was in Exp1 - Visual cue - transparent vs opaque Exp2 - smell cue - live mealworm in cup vs air-filled bag Exp3 - Auditory cue - Live mealworm with paper, dead mealworm with paper If only one cue, still did pretty good if that was vision. Dropped for smell and hearing. If two modalities, significantly better, if with vision. A+O not as good. Best scenario was with all 3 modalities, showing that multiple sensory systems better than just one

Model

Make assumptions about how things work, then try to figure out what logically follows from those assumptions in the hopes that it will help us choose what kinds of studies to do

EXPERIMENT - Entrainment of Rhythm in Teleogryllus Crickets

Male crickets typically start singing a few hours before sunset and stop a few hours before sunrise. The reason they start a little before sunset is because there is some jostling among male crickets to get the best spot for intercepting females because they want to be cosest to females. Stop before sunrise because while singing, they are not feeding, so they get hungry and need time to feed before they hide to avoid predators. Females become active around sunset and are in burrows before sunrise, so biological circadian rhythms for both males and females. Females don't have to sing, so looking for males but have more time to feed, which is important because making eggs takes energy. If you bring a cricket into the lab and keep in constant light, then its activity pattern will be offset each day because the natural rhythm is about 25 hours long - staggered pattern on the graph. This is the unentrained (free running) rhythm, not tuned to anything, just biological. When you entrain t

CASE STUDY - Palolo Worms

Marine worms in the south pacific that produce a long string of reproductive segments loaded with eggs or sperm. When it's time to spawn, the reproductive portion (epitoke) swims away. At the right time of the year, the worms start growing the extra segments whose sole purpose is to produce eggs and sperm. THey don't meet up to mate with one individual, instead releasing their gametes into the water. The gametes hang out in the deep water until it is time and then starts swimming up to the surface. All the epitokes star arrive at dawn one day a month (circadian rhythm), on the morning of the last quarter moon (lunar rhythm), during Oct, Nov, and Dec (the breeding season - circannual rhythm). They have basic nervous system structures (ganglia). So there's enough sensory information to swim up to the surface, but no more guidance than that

Moose Nutritional Constraints

Moose typically feed on low-salt grasses and shrubs. They periodically seek out high-salt aquatic plants (even though they are low in energy) because salt is a limiting nutrient and aquatic plants concentrate it

Naked mole rats don't have rhythms

NMRs live their entire lives underground in a dry, tropical climate. Because light and temperature don't fluctuate, there is no rhythm of activity

EXPERIMENT - Northwestern Crows and Shellfish

NWC have a specialized way of breaking shellfish along the rocky shores of the pacific northwest. They drop shells onto hard surfaces in order to break them. Crows are picky. They will often skip over several whelks before selecting one. Once they start working on a shell, they don't quit and try to find a different shell to break. All crows flew up to about the same height and dropped shells from about 5m. Researchers tested to see if crows' preferences were based on the size of the whelk. They preferred larger whelk. Next, they dropped the actual shells from various heights to determine how hard it was to open them. They found that large whelks always had a 25% chance of breaking upon dropping. Explains why crows don't give up and fetch another whelk, because same probability of breaking. Large whelks are the easiest to break and the optimum height for dropping is about 5m. Takes energy to travel to that elevation each time, and larger whelks result in larger net caloric intake

EXPERIMENT - Tool use in crows

New Caledonian Crows use tools. If you give them a big cylinder with food at the bottom, with a piece of wire, they will try to fish it out. If they don't get anywhere with that, they pull out the wire and walk over to the corner of the container to modify the wire. They make the wire into a hook to better fish out the food or throw rocks into the cylinder of water to raise the water level and get the food to a position that is easier to reach

EXPERIMENT - Indigo Bunting Star Compass

Night-flying migrants hypothesized to use star patterns as a compass (migrate at night). In aviaries in captivity, buntings become very active in Spring and Fall, when supposed to migrate. They seemed to move to south sides in fall, north in spring. This is migratory restlessness, that reflects the fact that they would be migrating at this time To record the orientation or average direction of captive birds, researchers used a funnel cage. If you put the bird in the funnel, it is a conical structure with a lid and line the interior with paper that will show scratch marks, it can locate them and decide where the bird wants to go. To manipulate the star pattern, researchers placed birds in a planetarium. 1. Normal - Orientation to South 2. Rotate 180 = orientation to north 3. Clockshift with normal stars - doesn't matter, oriented south 4. North star removed - orientation to south 5. North star surrounding pattern removed - random orientation Birds have learned the north star patter

Sea Turtles - Gyre Migration using Magnetic Maps

Once in the current system, they want to stay there for 10-15 years. The turtles do not move around passively while here, they are actively guiding themselves. They use positional map information and not just a compass from Earth's magnetic field. The map information comes from earth's magnetic inclination angle (the angle that the incoming magnetic field forms with Earth's surface, steeper toward the north pole, closer to 0 at equator) and magnetic intensity (stronger toward the poles). Line connecting where the inclination angle is the same are called isocline. Line connecting where intensity is the same are isodynamics. Each area on earth has its own unique magnetic address based on where the lines intersect

Human Sleep-Wake Cycle

Perception of darkness by the eyes Processing by the SCN Signals sent to pineal gland Production of melatonin Maximal likelihood of sleeping about 2 hours before peak production at night

EXPERIMENT - Vigiance Effect in Pigeons

Pigeons are found in flocks of different sizes. Researchers targeted the pigeons in flocks of different sizes with a goshawl to see if a flock was protective for pigeons or not. As flock size goes up, success rate of the goshawk goes down. With a larger group, there are more eyes to notice the hawk when it is farther away, so it can react sooner. IF just one pigeon, didn't notice the hawk until 3m away. If 2-10, 20m. IF 11-50, 40m. Spotted when way far away, gives them time to get away.

EXPERIMET - Rufus Hummingbird Migration

RH breed in the pacific northwest, then migrate south in the fall. But the problem they encounter is that they can't store enough fuel to complete the journey in one go, so they have to make a stopover in the Sierra Nevada Mountains. Researchers documented their behavior, waiting until they arrived, capturing and marking them, then releasing. This way, they were able to watch the individual hummingbird behavior and monitor their territory size. Then, they tried to estimate territory quality by trying to count the number of flowers in each territory. They also created a scale on their perches to monitor weight without disturbing behavior. An increase in weight gain correlated with a decrease in territory size after a certain point, because they became more efficient, expended less energy, and spent less time defending.

EXPERIMENT - Whip Tail Lizard and Conspicuous Activity

Reducing activity is a way to reduce conspicuousness. WTL were placed in large experimental pens. Added 2 predator leopard lizards to half the pens. Whiptail lizards in predator-present pens were less active.

EXPERIMENT - Numerical competency in New Zealand Robins

Researchers designed a branch with two covered cache sites. While the robin watched, they placed different numbers of mealworms one at a time in the caches. Which cache will it go to first? When the total number of food items in both is less than 10, robins preferred larger caches. Beyond that, not statistically significant. But were the robins just keeping track of the total volume and not relaly counting? In a second experiment, researchers mixed mealworms and rocks so that each cache had the same numbers and volume of objects, but different numbers of mealworms. They found that the robins were not just looking at total number of stuff, but specifically what items were being put in

Sea Turtles - Testing Magnetic Intensity Changes

Researchers picked one inclination angle of 2 different intensities to see if turtles responded differently to varying intensities. At point a intensity (eastern coast of US), turtles traveled east. If at point b intensity (closer to eastern atlantic) turtles traveled west. Because the only thing that changes intensity, we know that they are sensing the strength of the magnetic field. They are using magnetic responses as markers of position relative to goal.

EXPERIMENT - Ant salt foraging

Salt is a limiting nutrient for ants. They can get their salt from road salt put down in the winter. The salt leaches from the road into the surrounding areas. But the farther away from the road, the less salt there is. The foraging of the ant changes based on distance from the road. Examined recruitment to food vials by ant along 4 transects. Half contained sucrose, half contained salt. Transects were 1, 10, 100, and 1000m away from the road. Recorded number of vials of each that contained ants. Close to road, < 10% vials were visited by ants. Ants recruited to salt vials more strongly as distance from road increased. Even though those vials had less energy

Misdirection Examples

Skink with blue tail - this species can drop its tail to distract predators. It attracts and misdirects the predator, and the rest of the animal runs away Hognose snake - if crypsis fails, it flattens its head and acts like a viper, or acts like it is dying in agony, or if that fails, it just plays dead Owl butterfly - brown perched on brown tree trunk can blend in, but also have bright yellow eyespots that make it look like an owl, scaring off birds that approach it

Biological Rhythm

3 components - 1+ biological events that reoccur in time - in a repeated order (predictable) - with a repeated interval between occurrences (pattern) These are the ways that organisms adapt and live with the environmental rhythms around them - such as the spin of the earth, the movement of earth around the sun, and movement of moon around the earth.

Sea Turtles - Light Cues during offshore migration

An artificial beach crawl with a runway was developed. A very dim light box was placed at the other end, about as bright as reflective starlight. A turtle was grabbed and placed at one end, with light at the other. Some crawled to a light in the east, others to a light in the west. Just before reaching the light, they are carried in complete darkness and tethered to swimming arena to see what direction they would swim. If east, east. If west, west. If no light was provided, any direction. So, hatchlings set their magnetic compass by using environmental cues - these have to be learned because there are different beach locations

Search Rate Hypothesis

Animal detects cryptic prey and slows down the rate of search to find more

Search Image Hypothesis

Animal forms a mental image which helps it focus on the visual features of the prey

Cut neural inputs FROM SCN to rest of brain

Animal is arrhythmic

Cut neural inputs TO SCN

Animal is still rhythmic

Animal Compasses

Animals can use environmental cues to tell where they are. An animal shows orientation when it faces or travels a particular direction

Diminishing returns

Animals using a food patch reap diminishing returns as they use up the food in the patch. With time, the food will become more rare, and search and handling time will go up, the possibility of staying in that place will go down. When a forager enters a food patch, it initially harvests food at a high rate. But as the patch is depleted, its harvest rate declines. The decision to move on or not should logically depend on the value of staying at the patch versus the difficulty of finding a new patch.

Optimal foraging theory

Assumes that natural selection has favored feeding behaviors that maximize fitness. Many OF models assume that fitness increases with energy intake rate (that is, the more calories an animal can find, the better, because it will funnel less excess energy into reproduction) But, also need to include the cost spent to obtain the energy os models can look at some measure of the benefit - cost = net benefit

EXPERIMENT - Salmon Competition and Predation

Baby samon are predators of insects but are prey for larger fish like a brown trout. Method for determining how much risk a baby salmon will take to get a fly - basically, the bigger the fly, the bigger the risk the salmon will take. The salmon are more likely to go to fly if it is closer than farther. Can simulate a predator by placing a picture of the brown trout against the glass of the tank. Can simulate a competitor by holding up a mirror against the glass of the tank. Distance traveled is increased with presence of a competitor, decreased with presence of a predator compared to the normal

EXPERIMENT - Time sense of bees

Bees have the ability to learn what time of day different flowering plants are blooming and have the highest nectar supplies. Experiments show that they can distinguish time intervals as short as 15 minutes. Showed feeders in the vicinity of the hive at certain times, one at 9am, 10am, and 3pm. They fill these feeders for about a week, so the bees got used to it. They kept track of where the bees went and the bees showed up at the feeder sites at those times, even if no food to find. They knew when to expect food and where. Right place at the right time. Difference between filling times could be as low as 15 mins apart, up to 6 sites. This tells us that the bees have time sense - a function that keeps track of time. Accuracy of the arrival seems to depend on an internal biological clock related to metabolic rate - if you slow it down by chilling or exposing the bee to CO2, the bee's time sense is off, suggesting the existence of a biological clock. If they did this for 2 hrs worth,

EXPERIMENT - Bluejay foraging - Search Image Hypothesis

Blue jays are pretty easy to train. Researchers trained the birds to search for moths on a computer screen. If contained a moth, clicked a button. If not, another button. IF correct, food reward. If incorrect, dim lights and try again. Trained initially with easy to see moths, then switched to cryptic moths Created the following conditions 1. No moth or catacola relicta 2. No moth or catacola retecta 3. catacola relicta, catacola retecta, or no moth Each picture was a challenge for the bird to solve. If forming a search image, initially ot it wrong, then became more careful, looked for the moth, found the moth, and made search more efficient. They became better with practice, and got familiar with what it looked like. In both of the runs with just one species, the percent of correct responses increased with time, but this alone does not tell us they are using search image hypothesis. The information that was useful was that IN the nonrun treatment (both species mixed), the percent

EXPERIMENT - Bobwhite foraging, search rate hypothesis

Bobwhites are small ground-dwelling quails that run around and eat seeds and bugs off the ground, in a very efficient manner. Researchers trained the birds to feed on food pellets on the floor of a large room. Then, tested birds to see what happened if the pellets became cryptic. Measured how quickly the birds scanned to find the food. Results showed that the more cryptic the prey, the more slowly the birds walked around the room. Search speed decreased as crypsis increased.

EXPERIMENT - Bayesian foraging in bumblebees

Can bumblebees estimate food patch quality in a bayesian manner? Do they use prior knowledge to make decisions about patch use? They can learn about different kinds of patches and use that to make decisions about their foraging. Bumblebees were trained to forage from artificial flowers offered in patches. But not all patches were the same. Half the bees were trained in a uniform environment (5 of the flowers had nectar in each patch). The other half of the bees were trained in a high-variance environment (either 1 or 9 of the flowers had nectar in each patch. The bees had different experiences. Bees trained in the uniform environment had a low propensity to stay in a patch. After a bee finds one flower, it knows 4/11 remain, then 3/10, 2/9, 1/8. Each time, the probability decreases. For these bees, other patches with 5/12 rewards would actually be richer, so they give up quickly because it becomes less worth it to stay. Bees trained in the HV environment had a higher propensity t

Sea Turtles - Use of a magnetic compass during offshore migration

Can the turtles detect a magnetic field using their internal compass? Using a box lined with coil, an artificial magnetic field that imitated the earth was created for the turtles. In the interior of the box was a water pool with a center post and a rotating arm on top, with the turtle tethered. As the turtle swims, it would pull the arm to point in the direction of swimming. The turtles were woken up by turning on a lightbulb in one side of the box. With their compass sense, the turtles went NE in the normal magnetic field. When the field was reversed, traveled SW. But how do the turtles know to go E? Innate or Learned? lightbulb could be providing an environmental cue

EXPERIMENT - Catfish Predation

Catfish are famous for living deep in murky water, where visibility is low, so vision is not useful. But two other sensory systems could be - external taste (dissolved chemicals in water) and water movement (vibration) Researchers observed catfish hunting individual guppies. Used an infrared vide system to track the movement of both predator and prey in complete darkness. How did the catfish catch the guppy? They identified 3 types of movement as the catfish hunted - path following, head-on encounters, and attack on a stationary guppy. Path following was the most common. 80% of the time, attack occurred on moving guppies. Then, manipulated either the external gustation (reduced ability to detect chemical cues) or the lateral line (reduced ability to detect hydrodynamic cues). Success rate dropped a little with taste ablation, about 5%, but dropped more significantly with ablated lateral line, suggesting that the lateral line is more important for catching prey. A catfish with an a

EXPERIMENT - Batesian Mimicry in Kingsnakes

Coral snakes are venomous. Kingsnakes are not venomous but possess similar coloration. An animal that has evolved to avoid coral snakes might also evolve to avoid kingsnakes. Staked out plasstic snake models in areas with and without native coral snakes. Some brown and cryptic, others with kingsnake pattern. They checked to see if teeth marks were left in the models and counted predation attempts. The percentage of cryptic snake models attacked in each area was about the same, suggesting equal number of predators. In areas where coral snakes live, the kingsnake models were rarely attacked. Where coral snakes were absent, kingsnakes were attacked at a higher level because they are so conspicuous they get attacked even more. The predators that don't experience coral snakes don't seem to avoid their knockoffs

EXPERIMENT - Kangaroo Rat Activity

Data was collected on a scrolling paper trace. A black mark on the paper indicates a rat has entered a feeder. Based on where the mark is, can read time. The kangaroo rat has 3 phases of activity 1. Nov - Mar - nocturnal (no activity from noon-6pm, then active overnight, indicating a circadian rhythm). There were white diagonal stripes that show that they avoid bright moons (like a full) and anticipate the moon rise (lunar rhythm) 2. April and May - Lunar rhythm was lost 3. Summer - circadian rhythm declined The kangaroo rats eat seeds and insects. However, they are found in the desert, where it is hot and dry, and insect life is decreased because of this. Food is harder to find in the summer because seeds are still being made and insect activity is lower. Then, they don't have the luxury of confining their activity to solely overnight, they are too hungry. Can't pay attention to the lunar rhythm because food is starting to go away. There is a risk to going out in the nighttime because they are more visible to predators in the moonlight. As the food supply gets better, temperatures change, seed production hits a high, and there is a return to a circadian and lunar rhythm.

Teaching Behavior

Defined as "active participation of an experienced individual in facilitation learning by a naive individual" 1. Teacher modifies its behavior only in the presence of a pupil 2. Pupil acquires knowledge or skill more rapidly due to behavior of the teacher 3. The behavior is costly to the teacher (debated)

EXPERIMENT - Cryptic coloration in crabs

Do crabs actively behave to take advantage of their cryptic coloration? Have a pink pebble-like coloration. Individual juvenile crabs were tethered on ceramic tiles in the ocean that were either a uniform white color or a heterogeneous shell-hash color. Recorded survival of all individuals over time. 30% of crabs on white survived, 60% of crabs on shell-hash. So, cryptic coloration does help protect them. They gave the crabs the choice of resting on white or shell-hash tiles. They manipulated predation risk for half the crabs by adding water from a tank containing predatory fish. Controls given plain sea water. Small crabs (blue bars) always preferred the shell-hash. Large crabs (range bars) showed no preference at low predation risk, preferred shell-hash when risk was high.

EXPERIMENT - Social defenses in killfish

Do fish form schools to protect against predators? Predicted that fish should prefer to associate with larger groups rather than smaller if predation is an issue. 4 treatments 1. high predation risk - dilute killfish skin extract added to tank (simulates predation event) 2. Predation cue and food added to tank 3. just food added to tank 4. control water added to tank Then measured the size of schools that the fish formed. No schooling in response to food or plain water. Formed the largest school possible with given group (10) when predation risk seemed high. Decreased school size when smell of food is also present, a trade-off There is a diluted risk when you are in a crowd. If a predator shows up, odds are 1/10 instead of 1/1. Also, confusion of the predator when it shows up. If they start zigzagging around, it is hard for the predator to target one fish, so the effectiveness goes down. Vigilance is an added benefit - multiple eyes are better than just 2 on the lookout

EXPERIMENT - Tool use in dolphins

Dolphins use marine sponges to protect their snouts as they hunt bottom-dwelling fish. The seafloor is strewn with sharp rubble and they'd all get scraped up otherwise. Individuals place basket sponges on their rostrum to forage in the rubble. It turns out this is the best way to catch the fish out of the rubble. This is a learned behavior that is passed from mothers onto daughters. Females spend years with their calves and sponging for fish is a fairly low-cost way to get food. Since the mother is with the offspring so long, there is time to teach them. The mothers rarely teach their sons because the daughters stick around in the area while the sons disperse to different places, they are with their daughters longer

EXPERIMENT - Drosophila circadian rhythm

Drosophila have mutations in the per gene that can generate new rhythms. In WT, 12/12 24 hour cycle. In a long period mutant, more like 14/14 cycle. For arrhythmic, just a totally random biological rhythm. In the short-period, more like a 9/9 cycle. Changing just one part of the gene can change the biological rhythm Fruit flies are most active at dawn and dusk, probably because of the ideal temperature. Fruit flies have an oscillating pattern - per and tim genes work in a negative feedback loop. Their quantities build up, and if they get to be too much, they turn themselves off and quantities go back down. The per and tim genes are transcriped. THe mRNA is translated. Enough concentration = dimer together. The dimer is a txn factor that turns on/off certain genes so when per/tim is present, cell actiivty is different. Exactly what the cell is doing depends on how much dimer is present. When per/tim gets abundant/hits a threshold, per/tim turns off its own genes, so you get a negativ

Generalists

Eat most types of food, have larger handing times but lower search times

Specialist

Eats only a few types of food, have smaller handling times but larger search times

EXPERIMENT - Shark electroreception

Electroreception is the ability to detect electric fields. An electric field can travel from its source in water but not air, so it is useful for aquatic species. Researchers created a setup with a testing tank with sand on the bottom. Water entered the tak through a buried pipe and emerged from the sand near the other side. Tested to see if shark was using olfaction or electroreception. 1. Buried live flounder under the sand - shark made accurate attack (smell + electric field available) 2. Live flounder in an agar chamber - shark made accurate attack (smell + electric field available) 3. Flounder pieces in agar - attack at displaced odor site (only smell) 4. Buried live flounder with plastic insulation - no attack (no smell or electric field) 5. Plain electrdes - shark attack 6. Plain electrodes vs actual chunk of dead fish - attacked electrodes first, then turned around and got the fish, suggesting that it prefers something alive.

Profitability

Energy taken in / handling time Better with shorter handling times

EXPERIMENT - Apple Snail Specialists

Few animals eat apple snails because they are large, hard to handle, and can seal themselves up with a trap door (an operculum) - MAJOR HANDLING TIME. Snail kites have adaptations that change the handling time. They have hooked beaks and huge curved talons ideal for opening apple snails

EXPERIMENT - Fiddler Crabs and Tidal Rhythms

Fiddler crabs feed on prey found on mud flats. During high tide when the mud flat is covered with water, they take shelter and hide in burrows. They need to be in burrows before the high tide arrives so they have a tidal rhythm, so they can anticipate the rise because of this. But, the tidal pattern is different in different areas. Because they can adjust their tidal rhythm and tune it locally, they do. In Costa Rica, crabs of the same species are found on both the Caribbean and Pacific coasts. In each place, the crabs have tidal rhythms that match their respective local tides. If you transplant the crabs from the Caribbean coast to the Pacific coast, and let them hang out for 5 days, learn the pattern, then measure the rhythm in hte lab without tides, the transplants now match the Pacific coast tidal pattern. As a control, experimenters brought some over and tested them without letting them situate to the pattern. This is an example of entrainment

Lateral line system

Fish have a series of sensory structures that detect movement, flow, and pressure changes in the water. Ex. Hair cells inside a bubble, as bubble gets pushed the hairs trigger action potentials that give sensory info. Can compare info from both sides of body to localize source of movement. They also have external chemical senses and can sense chemicals in water from external taste receptors

EXPERIMENT - Patch use by fruit bats

Fruit bas are diurnal animals that feed on fruit and nectar. In this study, researchers designed a feeder that provided diminishing returns - much like a patch of food in real life. Do they all agree as a species when returns are not worthwhile? Researchers created a way to make slurping the liquid more difficult as level goes down. They simulated diminishing returns by placing bits of rubber in the feeder, that made it harder to suck out as levels went down. As they were feeding longer and longer, total amount of food harvested increased, but rate of decrease slowed down, indicating diminishing returns Bats in the outdoor cages were given 3 identical feeders that contained a protein-sugar mix, but concentration of sugar was different in each. The bats all quit using the feeders at the same net reward, the same giving up density, where each one had the same amount of sugar per sip remaining in he feeder. So in the lower concentrations, more liquid left. Thus, the reward per feeding at

EXPERIMENT - Innate avoidance by the great kiskadee

GK are birds found in Texas that prey on snakes but avoid the poisonous coral snakes that live in the same area. Is this learned or innate? Researchers took eggs from nest and hand-reared hatchlings to see if they needed to be taught. They never saw the snakes before. Researchers did a test to see if avoidance was innate. Took wooden dolls and painted them. W+G ring was ok. Y+R ring not ok Y+R stripe was ok Coral snake ring and stripe were not ok They had distinct opinions about what was worth pecking at and what wasn't. Birds raised in captivity avoided the Y+R rings and coral snake rings and stripes despite never having seen a coral snake before, which demonstrates an innate behavior.

EXPERIMENT - Entrainment of Circannual Rhythm in Golden-Mantled Ground Squirrel

GMGS are found in the mountains, in the cascade in Washington state. Newborn squirrels were captured in the spring and raised in different conditions. 1. Normal light cycle - matching the outdoors environment both on a daily and seasonal basis 2. Constant dim light - no light cues - enough light for the squirrels to scamper around and dim enough to sleep if needed, but not high summer. In both cases, temperature was held constant at a cool temp 24/7 and food was provided constantly so no cues from social interactions with caretakers or from meal times. Randomized feeder refill times and cleaning times. Studied the hibernation patterns The first year, most went into hibernation at a similar moment, slightly different lengths of time, and came out at about the same time. The next year, hibernated at different times. Some had different lengths of time, all had different onset times. No environmental cues, so saw an unentrained rhythm. Rhythms continue in the absence of stimuli from

Use of Wave Cues

Hatchlings will not swim along shore because most of their predators are here. They want to go straight out, away from the shore, into the open ocean. The easiest way to do this is swim directly into waves to be taken away with the current. If placed out in the middle of the sea, turtles agree to swim in one direction, East, and during this time they are swimming directly into the ways. When wave direction is manipulated by picking days with different wind and wave direction, it was found that turtles adjusted their direction to again swim directly against the waves into them.

Light as an Environmental Cue for Sea Turtles

If a turtle swims toward a light in the east and then is tested in the darkness, it will swim east. If west, then west. They pay attention to their environment before orienting themselves, so it is learned. In real life, turtles pay attention to light when crawling on the beach.

EXPERIMENT - Yellow-eyed junco learned foraging

If foraging is a learned practice and if practice makes perfect, then older animals should be better at certain tasks than younger ones. Researchers presented mealworms to different ages of birds - recently fledged, young and older juveniles, and adults. Adults had the lowest handling times and the highest energy intake rates. Results suggest that adults had learned with practice and the benefit is greater efficiency

Warning/Aposematic Coloration

If poisonous, animals often carry signals that communicate this with other species. For example, poison dart frogs make their coloration very obvious so many potential predators will see the colors and run off, knowing they are poisonous. Evidence suggests that some predators have an innate avoidance of warning coloration, but others need to learn

EXPERIMENT - Entrainment of reproductive cycle in green anoles

In males, the growth of testes begins in the spring and depends on increasing temperature. Ovaries in females also grow back in spring - but seemingly not because of temperature. Females were kept in the following conditions 1. Alone - slow ovarian growth 2. With normal males - rapid ovarian growth 3. With castrated males - slow ovarian growth Castrated males don't show normal courtship behavior, don't do dewlap displays, don't produce testosterone or visual/social signals, pheromones. Possible explanations were either that normal males provide a chemical cue or social cue that is lost when testes are removed. Added a condition with dewlapless males - got slow ovarian growth. These males still had testes so still would have made chemical signals, allowing us to eliminate the possibility of a chemical cue that causes ovarian growth

EXPERIMENT - Sun compass of the European Starling

Starlings are daytime migrants and were hypothesized to use a sun compass. For this experiment, sunrise at 6am, sunset at 6pm. Sun moves through the sky at 15º per hour. Bird was trained that food would always be in the SW bin, but researchers didn't want them to learn from visual cues. So they rotated the bins so every time the bird experienced different physical bins in the same spot. For birds to use the sun, they have to pay attention to the time of day. After training, the birds were clockshifted by placing them indoors under artificial light with the lights coming on in the morning at a shifted time s the "sun" rose for the birds earlier. If teh birds were finding direction with a sun compass, then clockshifted birds should make predictable mistakes about where the SW bin was. If 3 hours earlier, and tested at 9am, the birds will think it is noon because 6 hours have passed since sunrise. So they will go to the S position. Then will turn 45º to reach SW. But, the sun wasn'

EXPERIMENT - Tool use in Capuchin monkeys

Stones vary in their size, weight, and composition, which affects their fragility. Capuchin monkeys use stones to open hard nuts. Researchers offered individuals a nut and stones that differed in functionality based on type (soft sandstone or hard quartzite) or size and weight (heavy or light). Recorded the first stone used to hit the nut - whichever the monkey chose first, with no opportunity to practice. They repeated this 5 times with different combinations of stone, and the monkeys always used the more functional stones based on its assessment of composition, size, and weight, assessed its features.

EXPERIMENT - Stotting behavior in Gazelles

Stotting behavior is a kind of alarm signal to other gazelles. But they also stot when alone and no one to warn. Makes pursuit less likely. Gazelles are very fast and can keep it up for a long distance, unlike their predators, cheetahs, who can run extremely fast but only for short periods of time. Stotting is a signal that can be read by their predators. Cheetahs are warned off when gazelles stot. So clearly involved in pursuit deterrence. Both species save energy. A full chase is exhausting and often unsuccessful for the cheetah If the gazelles stotted, the cheetah usually gave up and stopped stalking. When it chased, it lost 100% of the time. When the gazelle doesn't stot, the cheetah still ended up giving up the hunt, and chased/failed about 1/3 of the time. The rest, they continued and gazelle was killed. But if the gazelle stots, it always wins

EXPERIMENT - Tassel Ear Squirreled and pine trees

Tassel eared squirrels often reject many similar trees before accepting one; why do they spend so much energy? They need to avoid toxic compound named a-pinene

Sea Turtles - Natal Homing

The Geomagnetic Imprinting Hypothesis suggests that little turtles learn the magnetic address of their home beach and come back to it later as adults. Remember this address for 35 years and come back when it is time to nest. The life cycle takes a minimum of 20 years, so no good way to tag the adults and wait for them to come back because of size changes. Magnetic field lines criss cross the beach. If the turtles can recognize the field lines, they can know where they are along the coast. BUt the field lines move from year to year, because the liquid within the core of the earth that produces it doesn't move uniformly each time. Some years, 2 field lines can converge or diverge. This has implications for how preciselt the turtles can return to their nesting beach if they recognize the area as between 2 field lines. If converging, physical area is smaller, piled up on one another. If they are diverging, more area to nest. Over the years, tracking converging and diverging field lines

Crypsis

The art of blending in, usually a combination of appearance and behavior

EXPERIMENT - Chacma Baboons passing high-value foraging areas

The baboons sleep on the hillside, and pass through an arid grassland, pass through riparian woods that have lots of foraging value, and to the dry riverbed that has medium foraging value. In the high-value area, they are too exposed to predators, so it is too risky. In the medium, they can see far enough out to keep an eye out for the leopards (their predators) and still get food

Biological Clock

The internal physiological systems that track the environmental rhythms that often tune the rhythm to the environment

EXPERIMENT - Learned avoidance with monarch butterflies

The monarch butterfly larva feeds on milkweed which contains bitter-tasting and toxic akaloids. The adults taste nasty to most animals. Effect of MB toxins - naive blue jay tries one and learns to avoid it in the future. BJ were caged with Ms. They ate and threw up the MBs. Every individual that had that experience stopped eating the MBs. The individuals recognized the warning coloration and wouldn't eat closely related butterflies either There probably isn't a strong evolution to have this innately because there isn't a strong overlap in their territories, and doesn't kill them, just makes them feel bad. The small viceroy butterfly does not consume the toxic plant but it mimics the coloration of the MB so predators avoid it too. They can reap the benefits without the metabolic cost of eating the toxic compounds

Optimality

The simple idea that there may be more than one way to accomplish a goal and that one of those ways just might be better than the others. In other words, it is the OPTIMAL way. If in fact, there is an optimal way AND it is heritable, then the optimal way should be selected or and the suboptimal ones should be selected against (even though they also work to achieve the task). So, the animal's behavior should get sculpted by natural selection to be optimal, leading to a pure evolutionarily stable strategy.

Nesting Loggerhead Sea Turtle Life Cycle

The turtles are reptiles - air breathing. But they live almost entire life in the ocean. The eggs have to be laid on land so that the embryos will survive. Every 2-3 years, an adult female turtle goes to beach, digs nest, and lays eggs, in a cup hold about 1.5 ft deep, depositing 100-150 eggs, then leaves that site back to the ocean. Babies hatch, take a couple days to overcome trauma of hatching, and when sun sets and sand cools down, they get active and crawl up out of the chamber and break through. The turtles take off for the ocean. The turtles find the sea by crawling to the lowest, brightest horizon and away from large dark dunes and vegetation. Hatchlings have 2 journeys to make - crawling from nest to sea and swimming offshore to the gulf stream current. The pelagic juveniles spend approximately 10-15 years in the atlantic ocean in their gyre, their nursery habitat. Coastal juveniles establish coastal feeding sites after 10-15 years in ope ocean. They are able to come back

Sea Turtles - Detecting wave direction for offshore migration

The turtles will either move up back down forward (if into the wave), or up forward down back (if with the wave) because they are buoyant objects under the water. They can feel the movement of the wave above them under the surface in an orbital path. The turtles can use this cue to figure out a direction and how to orient themselves. A wave simulator with rotating arms was built to simulate the orbital motion. As the arms spun, so would the turtle. They positioned the turtle so the artificial waves came from different directions. When the contraption simulated a turtle swimming into the wave, they preferred not to turn. If a wave came from the left, the turtles turned left to swim into it. If a wave came form the right, the turtles swam right to swim into it. If the turtle was simulated swimming with the wave, they turned about equally the same way to face that direction. By detecting the sequence of movement that the waves propel them in, they can figure out what way the wave is

Handling time

Time to manipulate item prior to consumption (a way to include cost)

Optimal Diet Model

Tries to figure ut what decisions animals should make when selecting food items to eat. The model assumes that foragers maximize their fitness by maximizing net energy intake, food items are encountered one at a time in proportion to their abundance, food items can be ranked by profitability

Entrainment

Tuning of biological rhythms to local cues

EXPERIMENT - Teaching behavior in the White-Tailed Ptarmigan

WTP are chicken-like birds that are found high in the Rockies. Researchers observed that chicks follow the mothers for weeks. Mothers drop food and give a unique vocalization, a food call. Chicks then run to the mother ad feed. It looks like the hen teaches them. Researchers hypothesized that chicks should then primarily eat foods that are associated with their mother's food calls. (recall that chicks are precocial so mostly select their own food). To test this, they observed 7 hens and their chicks. Recorded food eaten by hen and chicks. Recorded all food calls given by the hen and the food plant associated with the call. There was a positive correlation between the proportion of food calls associated with a plant species and the proportion of that plant in the chicks' diet. Concluded that chicks learn diet from mother's calls. The mother alters her behavior, chicks' diet is influenced by this, the mother pays the cost of giving up food, time, and energy. Although the action its

EXPERIMENT - Pinon Jay scared by Hindwing moth

When the moths are at rest in a tree trunk, its top wings are spread and cryptic. Just before taking flight, it spreads its bottom wings to reveal a colorful pattern. Sudden flash of color in a cryptic situation would startle the predator. The researchers built a presentation board with triangular slots. Put a model moth (triangular box) with spring loaded paper wings. When you pull the box out, the wings are spread. They trained the pinon jays to get food by pulling the triangular box. ON the back, there was a pine nut that served as a reward. Initially trained the jays with plain gray wings. If they transitioned to surprise color wings, the birds got startled, and sometimes even dropped the box. This behavior increases the moth's survival and is selected for because more of these moths survive.

EXPERIMENT - Suprachiasmatic nucleus in hamsters

When the suprachiasmatic nucleus (SCN) is lesioned, the hamster loses its rhythmicity. At first, it is entrained to the dark/light cycle 12/12. If you take away light entirely, so it's just dark all the time, the rhythm still happens, but becomes staggered, and free-running. Then, an SCN lesion results in aperiodicity. Comparing hamsters with a sham operation, lost the rhythm. Most mammals have multiple biological clocks, but this is the main one. If you lesion the SCN of a normal hamster, it becomes arrhythmic. If you add back the SCN from a mutant short-period hamster, the lesioned animal will have a short-period rhythm.

EXPERIMENT - Cooperative defense of musk oxen

When threatened by a predator, the musk oxen form a circle around the vulnerable members of the herd. Babies in the middle are sealed off. So wolves give up because they can't take on a healthy adult successfully. They can only get the small ones.

Evolutionary arms race

back and forth processes of adaptation and counteradaptation in two species.