Entomology Midterm #1 Flashcards
Lectures 1-7
members of class Chelierata
spiders, ticks, scorpions
members of class Diplopoda
millipedes (2 pairs of legs per segment)
members of class Chilopoda
centipedes
members of class crustacea
lobster, crabs, crayfish, shrimp, barnacles
what is chitin
long chain of polymer of N-acetyl-glucosamine, a derivative of glucose
what is the ventral nerve cord
numerous ganglia along cord and associated with segments
what is an apterygote
a wingless insect
what are the three body regions
head, thorax, abdomen
what type of circulatory system do insects have
open - haemocoel
how do insects breath
with a spiracle/ tracheal system
describe the nervous system of insects
complex nervous system with a fair degree of encephalization
what is the chitinous cuticle reinforced with
proteins to form muscle attachments
what is an exopterygota
an insect that develops wings externally
what is an endopterygote
an insect that develops its wings internally
what is order dermaptera
earwigs
what is order Isoptera
termites
what is order mantoidea
mantids
what is order blattodea
cockroaches
what is order Hemiptera
true bugs
what is order Homoptera
cicadas, hoppers, aphids
what is order Coleoptera
beetles
what is order Hymenoptera
ants, bees, wasps
what is order Lepidoptera
butterflies and moths
what is order diptera
true flies
what mouth parts does a grasshopper have
chewing mouthparts
what mouthparts do order Lepidoptera have
coiled proboscis used to siphon nectar when extended
how many ganglion are in the head
5 ganglion per section
how many ganglion are in the thorax
3 ganglion
what is the purpose of ganglia in the abdominal section
to connect each leg and nerves
what are the 5 head appendages
antennae, labrum, mandibles, maxillae, labium
what are the four mouthparts derived from legs
labrum, mandibles, maxillae, and labium
what does the head capsule house
brain, mouth opening, mouthparts, and major sense organs (antennae, compound eyes, and ocelli)
what head appendages are posterior to the mouth and what is anterior to the mouth
labium, mandibles, maxillae, and labium are posterior and hypopharynx is anterior
what is plesiomorphic
mandibulate or chewing mouthparts (400 million years ago) with mandibles operating side-to-side
what is apomorphic
adaptation to ingesting solid food, filtering particulates from water, siphoning liquid foods and sponging liquid foods; includes haustellate mouthparts
what are the three different mouthpart positionings
hypothagnous, prothagnous, opistothagnous
what is hypothagnous
downwards directed mouthparts
what is prothagnous
forward facing mouthparts
what is opistothagnous
mouthparts are directed posteriorly
lacinia function
has teeth on inner edge to aid with chewing
what covers Lacinia when mouth closed
galea
what is a palpus used for
feeling
what is a palp
a segmented extension
what is an axillary palp
a small feeler-like structure arising from the maxilla
function of axillary palp
sensory function
what is a labium
the so-called lower lip, fused along the midline
what are the segments of the labium
glossa and paraglossa
what is a labial palp
one of a pair of small feeler-like structures arising from the labium
what is the cibarium
food cavity
what is the cibarium between
labrum and hypopharynx
what is the preoral cavity created by
Labrum, Cyprus, and labium
two major types of mouthparts
mandibulate and haustellate
what is mandibulate mouthparts
chewing and biting. generally mix saliva with food to aid swallowing
what is haustellate mouthparts
primarily used for “sucking up” liquids
what are coiled proboscis made up of
elongated galea of 2 maxillae
how many eyes do insects have
three simple ocelli and two larger compound eyes
what are stemmata
groups of lateral ocelli when compound eyes absent
what do ocelli not do
they do not form images. light sensing only
what is a biconvex
cuticular lens to transmit light to sensory cells beneath
structure of compound eyes
hundreds of hexagonal facets facing slightly different directions from its neighbours
how is a facet connected to the brain
each facet has its own optic nerve
do compound eyes produce images
On their own they do not produce images. Each facet generates information on colour and intensity of light
how is quality of image determined with compound eyes
determined by resolution (number of facets) of the eye and the insects distance
disadvantages of compound light
cannot find a mate using visual cues alone and poor images at a distance
two types of compound eyes
apposition and superposition
difference between apposition and superposition eyes
An apposition eye is well suited for vision in bright light, whilst superposition eyes are typically found amongst nocturnal insects
generalized form of antennae
filament
what is a setaceous antennae
bristlelike, with segments becoming thinner distally (e.g., dragonfly, cockroach)
what is a filiform antennae
threadlike, with segments uniform in size. Typically, cylindrical (e.g., ground beetle)
what is a moniliform antennae
similar to a string of beads, with segments (spherical) of similar size. (e.g., termite)
what is a serrate antennae
saw-like. segments more are less triangular, especially in the distal portion (e.g., click beetle)
what is a clubbed antennae
there are several types of clubbed antennae. the segments increase in diameter distally
what are the three types of clubbed antennae
lamellate, capitate, and clavate
what is a geniculate antennae
elbowed, where the first segment is long and the following segments are smaller and at an angle (e.g., ant)
what is a plumose antennae
feathery. most segments have whorls of log hair attached (e.g., male mosquito)
what is an aristate antennae
the final segment is typically enlarged and has a conspicuous dorsal bristle known as the arista. (e.g., syrphid fly)
what is a stylite antennae
the last segment has an elongate terminal finger-like process, known as the style (e.g., robber fly)
what is a pectinate antennae
comb-like. most flagellar segments with long, slender lateral processes (e.g., fire coloured beetle)
what function do antennae serve
strictly sensory
what function do mechanoreceptors have
detecting movement in the environment. provides sensory input about the position or orientation of the body and its appendages
what are mechanoreceptors innervated by
sensory neurons which fire when bent, stretched, compressed, or vibrated
how do mechanoreceptors respond during deformation
a charge from the nerve cell to the insect brain.
where are mechanoreceptors commonly found
on legs, mouthparts, and antennae
what is a chemoreceptor
a taste receptor
what do chemoreceptors respond to
to chemicals occurring on solid surfaces or in aqueous substrates, found on mouthparts, tarsae, antennae
what are olfactory receptors
usually thin-walled pegs, cones, or plates with numerous pores or slits through which airborne molecules diffuse.
what can olfactory receptors sense
low concentrations of compounds (i.e., sex pheromones)
where is the Johnston’s organ located
base on antennae, usually on pedicel
what are the two functions of a Johnston’s organ
proprioceptor and movement sound detector
what does a proprioceptor do
responds to movements of antennal flagellum and provides information about amount of air passing over it
and responsible for maintaining the insect’s sense of balance and orientation, especially during flight
what are the three segments of an insect thorax
prothorax, mesothorax, metathorax
what sections have wings on them
mesothorax and metathorax
what does each thoracic segment have
dorsal term, ventral sternum, and two lateral pleura
what is the coxa in an insects leg
the basal segment of the insect leg
what is the trochanter of an insects leg
leg segment between coxa and femur.
what is the femur of a insects leg
the third leg segment, comparable to human thigh bone
what is the tibia of an insect leg
the fourth leg segment, or “shin”
what is the tarsus of an insect leg
part of the leg beyond the tibia (~foot)
what does the tarsus consist of
several small joints, the last of which generally carries a pair of terminal claws
what is the arolium
a pad-like organ extended between the claws
in most flies what is the arolium replaced by
stout central bristle called the empodium
what are two additional pads called
pulvilli or pulvillus
what is venation
a system of thickened lines in the wings
what is the principal distinguishing factor in the hierarchy of insects
wings
what happens when front wings are thick (in Coleoptera)
protect both hind wings and body
what pair of wings are the flying wings
the hind wings
what are wings like in Hymenoptera
both pairs of wings are kept together with a hook like structure so that both wings act like one and flaps are more powerful
what are wings like in Lepidoptera
covered with tiny scales; scales are coloured or refract the light to produce pattern
what is a frenulum
Bristle near base of hind wing that holds front and hind wings together; found in Lepidoptera
what is a jugum
a lobe on the forewing of some moths which interlocks with the hind wing in flight
paleopterous wings
fold wings over back, lack third axillary sclerite and pleural wing folding muscle
how does flapping flight work in Odonata
flap both pairs of wings separately with the two pairs beating in opposite phase and are capable of flying in any direction without turning their bodies
what is articulation
wing flexing (folding), allows for protection and improved flight (rowing)
what does a reduction in wing weight lead to
loss of venation
what order has one pair of wings accosted with flight
coleoptera
what orders have a single pair of wings
diptera and strepsiptera
what orders have jointed wings
Lepidoptera and Hymenoptera
where are the wings attached to the tergum
“hinges”
what is the difference between diptera and strepsiptera
diptera has mesothoracic wings and strepsiptera have metathoracic wings
how does the direct muscle system affect wing flapping
when the inner muscles contract, the wings rotate about their hinges and flap upward. when the outer muscles contract, the wings are pulled downward again
how does the indirect muscle system affect wing flapping
the dorsoventral muscles contract to raise the wings. the tergum is lowered and the wings rotate about the outer hinges. the longitudinal muscles, running along the length of the thorax, contract to lower the wings. the tergum is forced upwards again, and the wings rotate in the opposite way about the outer hinges
what is the living layer of an insect cuticle
row of epithelial cells which are supported on a non-cellular basement membrane.
what separates the exoskeleton from the haemocoel
the membrane layer of epithelial cells
what are microtrichia
tiny hair-like structures on surface of cuticle
what is a trichogen cell
specialized epidermal cell that produces the shaft of a sensory hair
what is a tormogen cell
specialized epidermal cell that produces the socket of a sensory hair
generalized epidermal cells can differentiate into:
trichigen cells, tormogen cells, and dermal glands
generalized epidermal cells can differentiate into…
nerve cells supplying mechanoreceptors,
glial cells enveloping nerve cells, glandular cells, and oenocytes
what do glandular cells secrete
pheromones, defensive secretions, and wax
what are the two layers of the procuticle
exocuticle and endocuticle
what are the three layers of the epicuticle
cuticulin, wax layer, and cement layer
what are scales
flattened macrosetae that have evolved independently in several lineages
what are additional functions of bristles and scales
insulation, temperature regulation, sound absorption, chemical dispersal
how does colouration happen
either through pigmentation or physical interference (structural colouration)
what pigments are synthesized by the insect
melanin, monochromes, pterins, quinones
what pigments are acquired through diet
carotenoids and flavonoids
what are the structural colours
blue, whites, and all metallic, iridescent and opalescent
what are the two canals
dermal gland canals and pore and wax canals
where does the dermal gland canals go to
epidermis to surface
where do pore canals go to
epidermis to wax layer of epicuticle
what is apolysis
separation of epidermal cells from the inner surface of the old endocuticle (=formation of the subcuticular space)
epicuticle formation
cuticulin is laid down below the moulting gel and above the epidermis. next, the inner protein epicuticle is deposited just inside the cuticulin (chemically stabilized)
where are chitin microfilaments formed
beneath inner epicuticle
what is the process of insect moulting
1) apolysis
2) epicuticle formation
3) new procuticle deposition
4) ecdysis
5) procuticle expansion
6)hardening ad darkening
7) endocuticle deposition
when are ecdysial lines formed
formed in the cuticle that have little or no exocuticle.
what it old cuticle called
exuvium
what happens to eyes during a moult
the visual acuity is reduced during days before moult but it is then reestablished shortly after moulting
what happens during moulting
body lacks skeletal support, body maintained by muscle tone, susceptible to desiccation
do insects have regenerative powers
limited. if a leg is lost it will reappear during next moult
what is molting controlled by
one set of neurosecretory cells in the brain that stimulate corpora allata (small glands behind the brain) to produce juvenile hormone (JH)
what do prothoracic glands procduce
ecdysteroids (moulting hormones)
large amount of JH left after moult create
larva
small amount of JH left after moult create
pupa
no JH left after moult creates
adult
three functional regions of the digestive system
foregut, midgut, hindgut
what is the foregut called
stomodeum
what is the midgut called
mesenteron
what is the hindgut called
proctodeum
what happens in the midgut
digestive enzymes are produced and secreted, digestion occurs and absorption of nutrients
what happens in the hindgut
accepts waste from gut and Malpighian tubules, reabsorbs nutrients and water, and excretes waste
what is the intima
a lining of cuticle in the foregut and hindgut
what does the intima do
protects gut and regulates movement into and out of the gut
how may preliminary digestion occur in crop
salivary enzymes brought in with food, or midgut enzymes regurgitated
