Insect body plan (construction)

Question 1

What are their 3 distinct parts?

Answer 1

Head, thorax and abdomen
•larvae will not have distinguishable segments (+silver fish)
•made of 20 segments in total
•head develops from 6 (mouth and sensory organs)
•thorax develops from 3 (pro, meso and meta thorax)
•abdomen forms from 11 segments (reproductive organs and gut)

Question 2

The head (general points)

Answer 2

• like the computer - responsible for lots of processes (like the brain)
• where food enters the gut
• large compound eyes and antennae - most prominent features
• oscellae on head which detect light differences

Question 3

Antennae

Answer 3

•covered in chemoreceptors - e.g. detecting that let off by F, by M mosquitos
-can detect single molecules
•the base allows movement in all different directions
•large SA of antennae = more likely to detect chemicals in air

Question 4

Compound antennae

Answer 4

•used for movement
•covered in mechanoreceptors
•gives info about environment its exploring
•often nocturnal insects to feel in dark
-longer and thinner can detect more

Question 5

Antennae in collembulla and diptera

Answer 5

Diptera - antennae very small (paleoptera)
•rely on visual inputs sp have better eyes instead
•flies have bulbous structure at base of antennae giving them altitudinal info during flight
Collembola
•use antennae for precopulatory mate guarding

Question 6

Mouthpart bauplan

Answer 6

•head of 6 segments which has paired appendages
•clypeus - forms upper lip and tongue of mouth (prevents food out)
•labrum - prevents food out, covered in chemo and mechanical receptors
-involved in tasting and feeling food
•mandibles - chewing power and hardened grinding surface
•maxilla - handling and manipulating with palps on side aiding
•at back is labium - palps attached like lower lip

Question 7

Diversification of insect mouthparts

Answer 7

Orders will be characterised this way
•Lepidoptera - use coiled maxillae to drink nectar
•true bugs - straw-like for hypodermic piercing for piercing tree phloem or insects
•flies - variation, mosquitoes piercing part from labrum
•grasshopper mandibles will get worn down
•beetles - biting and chewing

Question 8

Thoracic wings

Answer 8

•wings attached to mesothorax and metathorax
-only these two contain musculature for the wings
•many spp have thoracic outgrowths too
•wings have veins which can be used in different ways
-fore and hind wings can be closely linked via hooks

Question 9

Thoracic legs

Answer 9

•legs attached to basal segment giving angular rotation
-proceeding segment to leg moving contains muscles for movement
•legs can be used for moving on water, kicking matches (mating rights) and digging
•can stick and grip to surfaces through Van Der Waals forces

Question 10

Wing morphology variability

Answer 10

Dragonflies - low energy, stable flight (individual control over wings make them aerodynamically stable, but not so manoeuvrable
Diptera - defining feature of haltiers, only have 1 pair of wings, very manoeuvrable
Parasite of grasshoppers and wasps have forewing as halter and hind normal (evolved twice)
•forewing may be a hardened case to burrow in wood = useful ecologically

Question 11

Abdomen

Answer 11

•not easy to distinguish 11 segments
•mayflies can see them as associated with gills
•M scorpion fly, piercer used to grasp F in mating
•ovipositor and genitalia found there
-F dragonflies have saw-like structure to make holes in vegetation for laying eggs