Final Flashcards
What are the two types of movement of gases within the tracheal system
a) diffusion
b) active ventillation
how does diffusion work during resting and during activity?
resting: distal parts of tracheoles are filled with liquid (not air)
activity: osmotic pressure of hemolymph increases (metabolic waste builds up) -> liquid is withdrawn from capillary tracheoles and oxygen is brought closer to tissue cells. as metabolic waste is oxidized and removed, osmotic pressure decreases = capillary force draws liquid back into tracheoles
describe active ventillation
contracting longitudinal and dorsal-ventral muscles flatten and telescope segments causing an increase in hemolymph pressure, air sacs collapse = active respiration
when muscles relax, decrease in hemolymph pressure = air sacs expand = inspiration
it is unidirectional rather than tidal.
e.g. first 4 spiracles are inspiratory, remainder are expiratory
what is the main idea of active ventillation
increase and decrease of volume in tracheal system
what are the two types of gas exchange in aquatic insects
- O2 from air
- O2 from water
what are the 2 challenges from getting oxygen from the air in gas exchange in aquatic insects
- potential water entry into trachea when submerged
- overcome surface tension at air-water interface
what are 6 solutions that aquatic insects have for overcoming the challenges of getting oxygen from the water
a) water repellent structures around spiracles
b) posterior spiracle(s) positioned on an extendable siphon
c) air sacs (extra-tracheal)
d) oxygen from tissue in aquatic plants
e) plastron respiration (plastron = film of gas)
f) oxygen obtained from water (spiracles are nonfunctional)
what are two water repellent structures around spiracles
- glands secreting oily substances
- hydrofuge hairs
what do extra-tracheal air sacs do in aquatic insects
- carry air bubble when diving
- spiracles open into air bubble
what are the challenges of extra tracheal air sacs in aquatic insects
- buoyancy: air bubble wants to rise to the surface. insect must swim down or get a grip on substrate (brime fly)
how do aquatic insects get oxygen from tissue in aquatic plants
spiracle at the tip of a sharp pointed abdominal siphon is pushed into oxygen-containing tissue of aquatic plants
how does plastron respiration take place
through specialized structures (close hair pile)
how do aquatic insects get oxygen from water
gills = site of gas exchange
what are the purposes of the alimentary canal and associated glands (5)
- lubricate
- store
- digest
- absorb food nutrients
- expel remains
when are alimentary canals long and short
long: herbivorous insects
short: carnivorous insects
what are the 6 types of feeding habits in insects
- green plant feeders
- fungi feeders (leaf cutter ants)
- predators
- saprophagous
- parasites
- parasitoids
what are the 3 types of green plant feeders
- monophagous - feeding on one plant species (cotton boll creevil)
- oligophagous - only feeds on a few species of plant (cabbage butterfly)
- polyphagous - many plant species are fed on (gypsy moth larvae)
what are 6 things that plant selection is based on
a) olfactory cues
b) visual cues (shape, colour)
c) random encounter
d) contact chemoreception
e) Infrared (western conifer seed bug)
f) degree of linearly polarized light (cabbage butterfly)
what is the degree of linearly polarized light
the amount of light that is polarized as a percentage of all light = degree of linear polarization (DoLP)
what are phagostimulants and phagodeterrents and when do you find them
phagostimulants: a natural food component that induces sustained feeding/a synthetic compound added to bait in order to attract insects
phagodeterrents: deterrence of an insect from eating something
found in contact chemoreception
what are the 2 types of predator feeding
a) active search
b) ambush
what are the 4 types of ambush feeding
- ambush with a device to enhance the probability of capturing prey (ant lion larvae)
- ambush with camouflage (assassin bugs)
- aggressive mimicry (mantids resemble flowers to capture prey, caterpillars resembling twigs)
- ambush with attraction of prey (bola spiders)
what do saprophagous insects feed on
dead or decaying plant/feces material (dung beetles, cockroaches, carrion beetles)
what is the difference between parasites and parasitoids
parasites feed off of their host (lice and fleas), parasitoids kill their hosts
what are the 3 types of unusual reproduction and post fertilization development
- parthenogenesis
- polyembryony
- viviparity
what are the 3 types of parthgenogenesis
- haplo-diploidy
- ameiotic
- meiotic
describe haplo-diploidy
parthenogenesis - oocytes undergo normal meiosis, fertilized eggs develop into daughters and unfertilized eggs develop into sons (hymenoptera, thysanoptera)
describe ameiotic
parthenogenesis - all offspring have identical genetic constitution as mother; all daughters (aphids)
describe meiotic
parthenogenesis - meiosis occurs but fusion of nuclei restores the diploid number of chromosomes, all daughters (some lepidoptera and orthoptera)
what are 2 possible advantages of parthenogenesis
- rapid mode of reproduction
- at low population density (when males are rare) the female genotype will survive
what is 1 disadvantage of parthenogenesis and 1 possible solution
- genotype in successive generations remains constant = adaptations to changing environments are slow
solution - one or more parthenogenic generations are followed by a sexual generation (aphids)
what is polyembryony
development of several offspring (larvae) from one egg. occurs in some parasitic wasps
what are the 2 types of viviparity
a) ovoviviparity
b) larviparity
describe ovoviviparity
oviparity - eggs are retained by mother just prior to hatching (tachinid flies)
describe larviparity
oviparity - gives birth to a larva or nymph, in viviparous diptera vagina is enlarged to form a uterus, reduced number of offspring but each with a better chance of survival (tse tse fly)
list the 8 leg specializations and what adaptations are present
a) running: femur, tibia and tarsus are very long to cover distance (cockroach)
b) jumping: femur thick with strong muscles and tibia is elongated (crickets, grasshoppers)
c) grasping: extended reach for grasping prey, tibia and femur fitted with spines (preying mantis)
d) swimming: coxa, trochanter, femer and tibia are paddle-like (water beetles)
e) pollen collection: tibia rows of hair ‘corbicula’ = pollen basket
f) legs for hearing (grasshoppers)
g) legs for courtship (damselflies)
h) legs for digging: shortened legs, fore legs short and flat, serrated edge helps to dig
name 2 structures used to grasp substrate
- claws
- adhesive structures
what are the 2 major theories of wing evolution and which one is most accepted
- tracheal gill theory
- para-notal process theory (most accepted)
describe the para-notal process theory
paranotum: lateral expansion of the notum
‘wings arose as lateral expansions (processes) of the thoracic
what is the evidence that supports the pro-notal process theory
-paranotal processes in cockroach fossils have venation similar to wing venation of living cockroaches
- 2 pairs of lobes (-> wings) beating together cause drag and turbulence
what are 6 adaptations that are pertinent to 2 pairs of wings
- reverse wing beat (odonata)
- hindwings reduced (hymenoptera)
- hindwings absent or modified - halteres (diptera)
- front wings are absent - halteres (strepsiptera)
- forewings are hardened and not used in flight (coleoptera)
- coupling of wings
what are the 3 types of wing coupling
a) frenate coupling: a frenulum (well developed hair) engages with frenulum hook
b) jugate coupling: jugum clips onto the hindwing
c) hamuli coupling: hooks (hamuli) along costa margin of hindwing catch into fold of forewing
what are 2 adaptations pertinent to each wing
- reduction of wing venation. wing veins may contain nerves, trachea, hemolymph
- reduction in pleating
what are the 3 articulations between thorax and wings
- anterior notal process articulates with axillary sclerite 1, AS1 also articulates with subcosta and AS2
- posterior notal process articulates with axillary sclerite 3, AS3 also articulates with AS2 and anal veins
- pleural wing process articulates with AS2
what two muscle groups are involved in moving the wings and what do they do
a) indirect flight muscles - move wing up and down
b) direct flight muscles - move wing forward, backward, twist wings
what muscles are involved in indirect flight muscles
- dorsal longitudinal muscles
- tergosternal muscles
what muscles are involved in direct flight muscles
wing extensor and depressor muscles
describe the process of moving the wings up and down
- when the dorsal ventral/tergosternal muscles contract, the notum is pulled down, notal processes are down in relation to the pleural process = wing elevation
- when the dorsal longitudinal muscles contract, insect shortens, notum is raised, notal processes are up in relation to the pleural process = wing depression