Entomology Exam 1 Prep

Dorsal Vessel

"insect heart"- pumps in one direction the tube runs longitudinally through the top of the thorax and abdomen, along the inside of the dorsal body wall. located on the posterior/backside of the insect

Body design of insects

- 3 major body regions: head, thorax, and abdomen - 3 pairs of legs - exoskeleton - compound eyes - antennae

Closed Circulatory System

- A circulatory system in which blood is confined to vessels and is kept separate from the interstitial fluid - found in Subphylum Annelida

Parthenogenesis

- Asexual reproduction in which females produce offspring from unfertilized eggs - pros: great reproductive potential, no risk of losing fitness by mating - cons: little mixing of genetic material

Gas Exchange

- Direct pathway via spiracles & trachea - Rapid oxygen delivery - Spiracles can be opened or closed to regulate gas exchange - tubing runs from the head to the tip of the abdomen to legs and antennae

Open circulatory system

- a circulatory system that allows the blood to flow out of the blood vessels and into various body cavities so that the cells are in direct contact with the blood - found in Phylum Arthropoda and Onychophora

Ecdysone

- a hormone that promotes molting - high concentration of ecdysone in the insect blood causes molting to occur

Auditory Receptor

- a sensory function that specialized nerve cells that detect auditory signals - tympanal organ: membrane stretched like a drum head to detect sound, located on leg or abdomen

Chelicerata

- a subphylum of arthropods - marine: Horseshoe crabs, sea spiders - terrestrial: spiders, scorpions, mites, ticks - two body regions- cephalothorax and abdomen - chelicerae look like fangs or pincers used to manipulate prey (first appendages) - pedipalp used for mating or as pincers (second appendages) - 4 pairs of legs - simple eyes - book lungs

Ecological implication of insect metamorphosis

- ametabolous: all life stages in the same habitat - hemimetabolous: all life stage tend to be similar environments and eat similar foods - holometabolous: larvae and adult are typically in very different habitats and eat different foods; larval insects and adult insects occupy very different ecological niches (little or no competition)

Arthropoda

- bilaterally symmetrical - exoskeleton - open circulatory system - trachea or gills - multiple body regions - jointed appendages - the second to evolve from Proto-Annelid & contains subphylum Hexapoda and class Insecta

Onychophora (walking worms or velvet worms)

- bilaterally symmetrical - gas exchange via the trachea - open circulatory system - exoskeleton (molt to grow) - link between worms and arthropods - the first appendages are antennae - third to evolve from Proto-Annelid

Annelida (ringed worms)

- bilaterally symmetrical - segmented body - gas exchange via skin - bristles on segments - closed circulatory system - one of the phyla to evolve from Proto-Annelid

Insect metamorphosis

- change from immature to adult, involves multiple changes in form during development but not all species have these stages - eggs, nymph, larva, pupa, and adult

Holometabolous development

- complete metamorphosis, adults look very different from larvae, presence of pupal stage - egg -> 1st instar larva -> 2nd instar larva -> 3rd instar larva -> ... -> pupa -> adult - ex: butterfly, moths

Polyphyletic group

- contains some of the descendants of a common ancestor, but not the common ancestor itself - does not represent a natural group

Monophyletic group

- contains the common ancestor and all of its descendent species - a natural group

Insect leg structure and types

- cursorial: running leg- long and slender - natatorial: swimming leg - fossorial: digging leg- highly modified foreleg to dig - raptorial: grabbing leg- praying mantis uses highly modified sickle-like foreleg -saltatorial: jumping leg- grasshopper - prolegs: caterpillars have abdominal legs

Insect digestive system/alimentary canal

- foregut: temporarily store the food, also has saliva - midgut: most of digestion and nutrient absorption occurs here - hindgut: excretion, plays important role in putting water back from waste, mostly about recycling - gizzard: acts as a grinder to make food particles smaller before it enters the midgut

Functions of insect body regions

- head: eyes, mouthpart, antennae - thorax: for mobility - abdomen: cerci, reproductive organs, digestion, and excretory system

Insects as human food or animal feed

- high feed conversion efficiency; could solve hunger for large populations - reduces environmental contamination - emit less GHG and little ammonia - requires less water - few or no animal welfare issues - low risk of transmitting zoonotic disease

Spermatheca

- in many insects, a sac in the female reproductive system where sperm are stored - can decide to fertilize or not

Insect hemolymph

- insect blood; a simple pumping system maintains a current of the blood - transports nutrients, hormones, and waste but NOT oxygen

Biodiversity and Abundance of insects

- just over 1 million species of insects - diversity can be across groups or within a group since there are different types of insects - diversity of case types found in the spectacular endemic Hawaiian Hyposmocoma moth radiation

Ommatidia

- light sensing units of the eye - sensitive to UV, serves as a pollen/nectar/floral guide

Strong benefit of complete metamorphosis

- little or no competition of niches - different life stages can use different habitats/resources and serve different ecological roles

Hexapoda

- meaning: 6 legs (3 pairs of legs) class entognatha - protura: cone-head soil organisms - diplura: two-pronged bristletails - collembola: springtails insects are Hexapoda but not all Hexapoda are insects

Mechanoreception

- mechanical pressure: moves or bends hair or setae; bends the cuticle surface - johnston's organ: located on the pedicel of the antennae - detects vibration, gravity, movement - helps flying insects manage flight -tympanal organ: a membrane stretched like a drum head to detect sound (on leg or abdomen)

Types of mimicry

- mimicry: the close resemblance of an organism(the mimic) to some different organism(the model) such that the mimic benefits from the mistaken identity - crypsis: the ability of an animal to avoid observation or detection by other animals - aposematic coloration warning mimicry - Batesian: an unprotected species (mimic) evolves to look like a protected species (model) - Mullerian: A chemically protected species (mimetic #1) evolves to look like another protected species (mimetic #2)

Hormonal regulation of insect metamorphosis

- molting between larval instar: ecdysone + high concentration JH - molting between larva to pupa: ecdysone + low concentration JH - molting between pupa to adult: ecdysone + no JH

Ametabolous Development

- most primitive - adults look basically identical to nymphs - egg -> nymph -> nymph -> nymph -> adult (sexually mature) - live in the same habitat - Ex: silverfish, bristletail

Head- Structure and Function

- mouthpart: for eating - eyes: to see, different types of eye - antennae: sends chemo and mechanoreception, sends signals from the environment

Abdomen - Structure and Function

- one of the insects body segments - function: spiracles along the side of the abdomen are part of the respiratory system, providing gas exchange. holds reproductive system and the digestive system, plus excretory system. also where cerci is attached to.

Book Lungs

- organs of gas exchange in spiders, consisting of stacked plates contained in an internal chamber - found in Subphylum Chelicerata - marine: book gills - terrestrial: book lung

Rectum

- part of the hindgut and the excretory system - where waste exits the body - focuses on the removal of water from excretion

Spiders

- part of the subphylum Chelicerata - have fangs and pedipalp (for mating)

Antennae Types

- pedicel, scape, flagellum, point of articulation, and antennal sulcus modified antennas: - aristate: hair sticking out, typical for flies - geniculate: elbow-shaped, found in ants and honey bees - plumose: 5 branches, found in mosquitoes and moths, maximizes the sensitivity of antennae for chemical cues - serrate: sawtooth-like antennae - moniliform: termites

Reason to study insects

- prehistoric roots - cultural importance: music, literature, haiku - agriculture: damage to foliage, piercing damage, disease transmission - medical/veterinary importance: transmit disease to humans or livestock - urban/structural: infestation in our homes - design innovations

Why study insects?

- prehistoric roots - cultural importance: music, literature, haiku - agriculture: damage to foliage, piercing damage, disease transmission - medical/veterinary importance: transmit disease to humans or livestock - urban/structural: infestation in our homes - design innovations

Male accessory gland

- produce spermatophore from the materials in the accessory gland- put a lot of effort into it - they inject spermatophore into the female body - transfer nutrients to females

Insect Brain

- protocerebrum: in charge of the eye - deutocerebrum: connected to the antennae, signals received by this part of the brain - tritocerebrum: related to the mouthparts - can be enlarged during swatting

Molting

- shedding skin; insects molt through their metamorphosis - exuviae

Hemimetabolous development

- simple metamorphosis, adults; look like nymphs except for wings - incomplete metamorphosis - egg -> nymph -> nymph -> nymph -> adult - wing pads (or wing buds) present in immature stages, but fully developed wings present only in adults - ex: stinkbugs and grasshoppers

Cerci

- singular cercus - used for sensing, mating, and attacking/capturing prey

Ocelli

- singular ocellus, eyes on top of the head - can have 1-3 - not sensitive to high resolution but change in light conditions - ex: ants, wasps/bees, butterflies

Respiratory organs

- spiracle: holes along the abdomen - trachea: largest airway, diffuse through the branches - tracheal branches: ridge structure to provide mechanical strength - tracheole: fine respiratory tube of the trachea, smallest airway

Insect wing structure and types

- structural color of butterfly wings: the change of the light produces coloration of the wings - haltere: in flies are flapped during their flight and function as gyroscopes, informing the insect about rotation of the body during flight

Crustacea

- subphylum of Arthropoda - ex: crabs, lobsters, barnacles, isopods (rollie pollie), and shrimp - in most cases have 2 antennas - 5 pairs of legs; isopods are the exception; some are biramous (dividing to form 2 branches) - 2 body regions: thorax and abdomen - gills are the respiratory organ * most similar to insects

Modifications of insect wing

- tegmina is a modified grasshopper's forewing into a leathery protective cover - elytra is a modified beetle forewing into a hard shell - hemelytra is a bugs forewing that is half translucent and half-opaque - light refractions change butterflies wings due to their scales -haltere wings: in flies are flapped during their flight and function as gyroscopes, informing the insect about rotation of the body during flight

Cephalothorax

- the main body region of a Chelicerata - the name of the major body part to which the legs are attached to

insect excretory system

- the process by which metabolic wastes and other non-useful materials are eliminated from an organism - malpighian tubules- similar to the kidneys

Reasons for the evolutionary "success" of insects

- tough exoskeleton - small body size - high reproductive rate

Structure of insect exoskeleton

-epicuticle (wax): outer layer integument waterproof -procuticle (chitin): made up of exocuticle (top layer) and endocuticle (bottom) -chitin: main chemical component of insect exoskeleton and crustaceans -rigid structure needed for muscle attachment -provide structural reinforcement

Ventral nerve cord

-ganglia: a mass of nervous tissue in an insect that is usually responsible for the control of an individual segment of the body -runs along the "belly" consists of paired segmental ganglia running along the ventral midline of the thorax and abdomen

Relationship among taxa

-phylogeny: branch of biology that deals with phylogenesis -phylogenesis: evolutionary development and diversification of a species or group of organisms, or of a particular feature of an organism -monophyly: derived from a single common ancestor -monophyletic -polyphyletic - as we move through the phylogeny, we get more "advanced" taxa

Different types of Metamorphosis

3 types: Ametabolous(primitive), Hemimetabolous(incomplete), and Holometabolous

Tracheal system

A gas exchange system of branched, chitin-lined tubes that infiltrate the body and carry oxygen directly to cells in insects

Spermatophore

A gelatinous package of sperm cells that is produced by males of species that they give to female species

Sociality in insect

ALL ants, SOME bees, SOME wasps and ALL termites -cooperation: brood care, in nest maintenance -overlapping generations (mother and adult offspring) -division of labor

Darin's live insects

Dung Beetle Weevil Darkling Beetle Harvester Ant Grasshopper Coleoptera Fly, Cactus Bug, Bee, Earwig

Choe's live insects

Thrips Cochineals Springtail?

Stadium

a duration of a particular instar

Diapause

a period of dormancy in which many insects undergo to avoid adverse conditions (eg winter cold absence of food). may occur during any stage of the life cycle.

Instar

a phase between two consecutive moltings

Structures on insect abdomen

abdomen has spiracles that allow air to enter through trachea

Proventriculus

aka gizzard acts like a grinder to make food particles smaller before it enters the midgut

Male/Female reproductive organ

both have an accessory gland male: spermatophore, aedeagus female: spermatheca, ovipositor

What is an insect?

characteristics shared by ALL arthropods (phylum) - segmented bodies - jointed legs - exoskeleton characteristics shared by insects - 3 body segments (head, thorax, abdomen) - 3 pairs of jointed legs - exoskeleton

Sexual selection vs Natural selection

choosing your mate based on appearance ie bigger horns vs the process whereby organisms better adapted to their environments are more likely to survive longer and produce more offspring

Centipede vs Millipede

class chilopoda: Centipede - one pair of leg per segment - have venom used to capture prey - fangs are appendages class diplopoda: Millipede - two pairs of legs on each segment - non-venomous - herbivores both - Subphylum Myriapoda - one pair of antennae - uniramous legs (not branched)

Territorial behavior

competitive behavior in which an animal tries to adopt and defend a physical area against others of the same species

Reflexive bleeding

defensive behavior in some insects where a noxious fluid is exuded by the insect when threatened. The fluid flows out through pores in the exoskeleton. tastes and smells bad ex: ladybug

Malpighian tubule

filamentous blind sacs that filter the hemolymph of metabolic wastes and transfer the wastes to the hindgut; similar to the kidney

Fat Body

function: groups of cells that store nutrients and part of metabolism /detoxification similar to the liver

Binomial Nomenclature

genus name + species name invented by Carolus Linnaeus ex: homo sapien

Compound eye

in arthropods, a visual system composed of multiple lenses; each lens registers light from a small portion of the field of view, creating an image composed of thousands of parts

Thorax- Structure and Function

prothorax: one pair of legs attached - mesothorax: one pair of wing per segment and one pair of legs per segment - metathorax: same as mesothorax function: for mobility

Insect molting process

sensory input (exoskeleton is too small!) -> brain hormone (stimulates the prothoracic gland) -> high concentration of ecdysone in the insect hemolymph -> molting occurs

Exuviae

singular exuvia- shed skin (older cuticle) that insects leave behind part of molting

Ostia

singular ostium; little holes along the dorsal vessel especially on the back side of the body

Stemmata

singular stemma; eyes on the side of the head, immature insects with complete metamorphosis

Insect body size

small body size - avoid predators, require a smaller amount of resources, niche availability - molting is more hazardous for larger animals - exoskeleton strength: may not be strong enough to support larger animals - respiration: many insects can only get enough oxygen to support small bodies

Chemoreception

taste - detecting chemicals often in fluid on the surface - receptors most often found on mouthparts, foregut, and tarsi smell - detecting chemicals in the air - receptors most often on or near antennae - receptors: hair, pegs, plates, pits function - determine if an appropriate host - sexual signaling - trail marking - alarm or defense communication

Aposematic Coloration (warning coloration)

the anti-predator adaptations where a warning signal is associated with the unprofitability of prey to potential preditors. the colors tell potential predators that they are toxic and distasteful- they stay from colors such as red, black, yellow, or blue

What is Evolution?

the development of new types of living organisms from pre-existing types by the accumulation of genetic differences in a population over long periods of time

Insect tagmata

the distinct body regions produced by the grouping and fusing of segments (head, thorax, abdomen)