UCR ENTM 010

What are the 3 parts of an antenna?

scape

pedicel

flagellum

What are 2 advantages of an exoskeleton

1. prevent water loss

2. shock absorption/defensive barrier

the __________ is an organ that distinguishes a female from a male, located at the end of the abdomen

ovipositor

what is the process called when an insect grows its new exoskeleton

molting or ecdysis

what are some of the reasons we study insects

medical/veterinary

economic

behavior

developmental (genetic)

what are the parts of an insect leg called in order from distance to body

coxa

trochanter

femur

tibia

tarsus

what is the circulatory system of an insect?

open circulatory system

dorsally located vessel pumps hemolymph from posterior to anterior

how do insects breath and what is the tracheal system of an insect responsible for?

- some small insects can diffuse through tissues

- tracheal system pumps oxygen

- some large insects use active ventilation

what is the classification hierarchy of insects, following the levels of the Systema Natura?

Phylum (arthropoda)

class (insecta)

order

family

genus

species

from the outside to the inside layer, what. are the 4 major components of an insects exoskeleton and what are they functions?

epicuticle - water retardant

cuticle - provide color/strength

epidermis - living cells

basement membrane - contain nutrients to maintain exoskeleton

the mandibles and maxillae of insects with piercing-sucking mouthparts have been modified to form?

stylets

the respective functions of the hindgut, midgut, and foregut are?

- excretion and water absorption

- digestion

- food acquisition and storage (crop)

what is the function of the proventriculus?

grinds up food as it leaves the crop

what is the functional difference between the compound eye and ocelli?

ocelli only used for light detection

both only found in mature adults

what is an advantage and disadvantage to piercing sucking mouthparts in an insect?

advantage: food is abundant

disadvantage: food is difficult to access

an insect found mainly in an aquatic environment would have which type of specialized leg?

natatorial

why can you cut off the head of an insect and it will still be responsive to its environment?

insect nervous systems are not centralized and are based off multiple ganglia per segment

in the nervous system, what are the axon and dendrites?

axon - long fiber portion of the neuron

dendrites - release and receive neurotransmitters

what are sclerites? and where are they located?

plates on the exoskeleton, held together with flexible membranes

what is evolution?

change in gene frequency in a population of individuals over time

what are the advantages and disadvantages of parthenogenetic species?

advantage: great reproductive potential

disadvantage: little mixing of genetic material, reducing the ability to adapt

what is the Johnston's organ, anyhow does it function?

sensory structure inside the scape; helps detect sound and movement in the air; lets insects know how fast they're traveling.

detects ripples in water for aquatic insects.

what are the different categories of development of metamorphosis? define them.

ametabolous - adults and nymphs wingless; no visible change in stage other than size

hemimetabolous - simple metamorphosis; immatures are wingless and slowly develop them over time

holometabolous - undergo complete metamorphosis; 4 stage life cycle (egg->larva->pupa->adult)

what is the function of the malphigian tubules?

act as kidneys; maintain constant hemolymph by filtering waste

what are magma in insects?

head, thorax, abdomen

what is the labrum's function?

Acts like an upper lip.

what is the Systema Natura?

hierarchical classification system used for describing/relating organisms to each other

what are the major steps form start to finish of the molting process?

1. apolysis (epidermis cells divide)

2. new epicuticle formed

3. cuticle deposited

4. ecdysis

5. expansion

6. darkening/hardening (tanning)

what is the difference between a spermatophore and a spermatheca?

spermatophore - ball of protein with 2 sacs of sperm carried by male and transferred to female (mozzarella cheese ball)

spermatheca - storage organ in females where sperm is stored and released when ready

what is the primary function of the protocerebrum in an insect's brain?

visual information

which type of insect legs deal with jumping?

saltatorial

what are spiracles?

openings in the body cavity where trachea are exposed to outside air

what are some functions of the accessory glands in female reproductive system?

- make a silk/glue substance to protect eggs

- create a shell with protein to protect egg from dehydration

- venom production

what is the name of the second set of wings in flies (diptera)?

halteres

what are the 3 segments from anterior to posterior that make up the thorax?

prothorax

mesothorax

metathorax

what are the structures covering the butterfly's wings called?

scales; provide camouflage and warning coloration

what is natural selection?

gradual/non-random process by which genes become more or less common in a population

"differences in fitness"

what are the of egg-laying types? Characterize

oviparous - normal egg encompassed in chorion (insect version of chicken)

viviparous - egg has insufficient yolk; juveniles retain/nourished by female; emerge live

ovoviviparous - egg has sufficient yolk; all nourishment; emerge live

if an insect has gills, where are they found?

abdomen

what is chemoreception?

the process by which organisms respond to chemical stimuli in their environments that depends primarily on the senses of taste and smell; primary structures = antennae

what is an example of a hemimetabolous insect?

Dragonflies, Grasshoppers, True Bugs, Walking Sticks, Cockroaches.

in the alimentary canal which of the 3 regions is the only place (inside and out of the insect) that is not covered in exoskeleton?

midgut (gastric caeca)

What is hemolymph, and what is its function in gas exchange?

blood of insects; serves no function in gas exchange

Fossorial legs are used for ____.

digging

What is artificial selection?

Evolution brought about by human-induced phenomenon.

in chronological order, what are the four major steps in the evolutionary history of insects?

1. development of body plan (head, thorax, abdomen)

2. development of wings/flight

3. development of wings flexion

4. development of holometabolism

what are the regions of the insect brain?

protocerebrum (eyes), deutocerebrum (antennae), tritocerebrum (mouthparts)

what is diapause? What can an insect do during diapause?

period of arrested development

insects stop growing/metabolism slows down to avoid unfavorable environmental conditions

why is an insect's waste typically solid and not liquid?

to help conserve water

exception: fluid feeding insects

what is the difference between univoltine, bivoltine, and multivoltine?

1. one generation per year

2. 2 generations per year

3. multiple generations per year

what is the purpose/function of antennae?

all sensory functions; smelling, touching, humidity detection, vibration, wind speed/direction

insect's circulatory system is _______ located and their nervous system is _______ located.

dorsally; ventrally

Who was Carolus Linnaeus?

A Swedish naturalist who developed the modern classification system. 700s

What is the visceral nervous system?

portion associated with the heart, gut, ventral nerve cord, and rear section of abdomen

what is a micropyle?

A small hole in the insect egg for sperm entry

where can you fin taste receptors on insects?

mouthparts, other areas of foregut, and tarsi of legs

what is the hormone that is responsible for stimulations epidermal cells of the exoskeleton to undergo cell division?

ecdysone

how many times faster does CO2 leave the insect tissue than O2?

25x

what is the function of hemolymph?

Ingestion of pathogens, forming a shield around large foreign particles, coagulation, transferring nutrients, waste products, and hormones around the hemocoel and is an internal lubricant.

the part of the insect that can be best describes as the "liver" is known as?

fat body; regulates blood sugar levels, stores fats, proteins, and glycogen. can also store metabolic wastes

what is sclerotinization?

occurs in cuticle; tanning agents cause proteins to chemically cross-link and cuticle darkens/hardens

what are the components of the foregut?

mouth, pharynx, esophagus, crop, proventriculus

what is the immature form of hemimetabolous insects called?

nymph

name the types of wings and give an example of insects that coincide with the type if wing

membranous (fly, bee, dragonfly)

halteres (fly; act as gyroscopic stabilizer)

elytra (beetle; tough exoskeleton, acts as protection)

hemelytra (true bugs, Hemiptera)

tegmina (grasshopper, cockroach, mantids, walking sticks)

what is the difference between passive and active ventilation?

passive - oxygen diffuses down into tracheal system

active - pumping abdominal muscles to pump air through tracheal system

what are the subphyla with the phylum arthropoda?

trilobita

chilicerata

crustacea

uniramia

What are ommatidia and what do they do?

individual structures that make up the light receptors in an eye. There can be more than 10,000 in a single compound eye.

what are tympana organs?

hearing organs consisting of a membrane stretched across frame backed by an air sac and associated sensory neurons

what features distinguish the phylum annelidia from arthropoda?

annelids - closed circulatory system and respire through their skin

arthropods - distinct tagma, jointed appendages, open circulatory system and trachea

what is the function of the pharynx?

To draw in liquid and solid food into the body.

why do insects dominate the planet?

1. tough exoskeleton

2. small size

3. rapid reproductive rate

4. extensive use of metamorphosis

5. evolution of sociality

6. wide variety of appendages

7. many species-isolating mechanisms

What is chitin?

a fibrous substance consisting of polysaccharides and forming the major constituent in the exoskeleton of arthropods

what are tracheoles?

The very small ends of the trachea where oxygen enters the cells.

what is the difference between apterygota and pterygote?

apterygota - without wings

pterygote - with wings

What is acetylcholine (ACh)?

ACH is a compound that is a neurotransmitter for synapses between motor nerves and muscles.

how do insects get rid of carbon dioxide?

CO2 diffuses through the tissues and out the integument

what is a stadium?

The time between molts of an insect, also known as instar.

What is the flicker-fusion frequency for insects?

The flicker-fusion frequency for insects is around 250 cycles per second or higher.

what are the characteristics of the class insecta?

Stagnant (main body parts: head, thorax, abdomen, pair of antennae, 3 pair of legs, 2 pairs of wings.

what are the major classes of the uniramia?

Diplopoda, chilipoda, Hexapoda (insecta)

what are the classification levels used in the systema natura?

kingdom, phylum, class, order, family, genus, species

what major advantage is conferred by holometabolous development?

allows for larvae and adults to specialize in separate niches; avoid competing for resources

what is the difference between the larval and pupal stages?

larva - juvenile stage of holometabolous insect

pupal - transitional stage between juvenile and adult; inactive stage

What is the flicker-fusion frequency for insects and what does this mean?

about 250 cycles/second; insects can scan an image 250 times per second allowing for clear resolution and rapid response to visual stimulus

how do some commercial insecticides disrupt the nervous system?

by inhibiting ACH's voyage across the synapse; constantly sending signal over and over until the insect dies

what is the male reproductive organ called?

aedeagus