L8 vision and the role of colour

Question 1

what forms the cornea in a compound eye

Answer 1

numerous individual ommatidia

Question 2

what makes up an ommatidium

Answer 2

a lens and nerve fibre

Question 3

what is formed when all the nerve fibres from the ommatidia converge

Answer 3

optic nerve

Question 4

what is an apposition eye

Answer 4

an eye in diurnal insects where the sensory receptor cells end close to the lens

Question 5

what is different about the eye of nocturnal insects and what is this type of eye called

Answer 5

they have a clear zone between lenses and sensory components = superposition eye

Question 6

what is the benefit of the clear zone

Answer 6

light can enter from neighbouring ommatidia

Question 7

what are the 3 ancestral photoreceptors in insects

Answer 7

UV, blue and green

Question 8

what insects have more colour receptors

Answer 8

Lepidoptera, Hymenoptera, Coleoptera

Question 9

what are the roles of ocelli

Answer 9

regulate daily rhythm
respond to large sudden changes in light intensity
detect horizon or roll

Question 10

where are ocelli found and how many are usually present

Answer 10

found between compound eyes
usually 1-3

Question 11

what are the 5 parts of an ocelli

Answer 11

corneal lens
corneagen layer
retinal cells
pigment cells
central nervous connection

Question 12

at what stage of life are insects likely to have stemmata

Answer 12

holometabolous larvae and sometimes adults

Question 13

what is the structure of a stemma

Answer 13

biconvex lens, cluster of photoreceptor cells (retinula) with crystalline core

Question 14

what effect do photonic crystals have on colour

Answer 14

produce coherent scattering = additive colour mixing

Question 15

what are interference colours and how are they produced

Answer 15

green blue, UV, metallics
reflection in multiple layers

Question 16

what effect can irregularities on an insects surface have

Answer 16

light scattering resulting in matt or pearly white colours

Question 17

what colours do insect not synthesise and what are the name for these colour groups

Answer 17

flavonoids - white
carotenoids - blue, red and yellow

Question 18

how can short-term colour changes occur

Answer 18

changes in spacing between reflective layers
pigment movement

Question 19

what is crypsis

Answer 19

selecting background where you appear less conspicuous

Question 20

what is deimatic behaviour

Answer 20

coloured parts suddenly being displayed, large eyespots

Question 21

what is the role of deflection marks

Answer 21

small eye spots deflect attention from head

Question 22

what is aposematic colouration

Answer 22

using bright colours to symbolise distastefulness due to toxins

Question 23

what are the 2 types of mimicry

Answer 23

Batesian and mullerian

Question 24

what enzyme catalyses light production

Answer 24

luciferase

Question 25

what is the main role of light production

Answer 25

sexual communication

Question 26

what do Diptera larvae use their light for

Answer 26

to lure and attract small insects into silk thread