Molting and Eyes

Question 1

What is Ecdyses?

Answer 1

It is another term for moulting and is important as it divides the life cycle of hexapods and other anthropods into a series of instars or stages.

Question 2

Moulting is taxon specific and can look very different for different groups, what can this process depend on and when does it stop?

Answer 2

It can depend on availability of food, temperature, and humidity.

Moulting stops after maturity

Question 3

How is moulting induced?

Answer 3

Through the increased production of ecdysteroids which function as moulting hormones

Question 4

What is the first step of molting?

Answer 4

Apolysis: the separation of the old cuticle from the epidermis

Question 5

What is the second step of molting?

Answer 5

Epidermal cells begin to secrete the new cuticle, starting with the outer layers and working inward

Question 6

What is the third step of molting?

Answer 6

Epidermal cells produce enzymes responsible for the degredation of the old cuticle. Up to 90% of the old cuticle is digested by chitinases and protease enzymes that recycle the old cuticle.

Question 7

What is the fourth step of molting?

Answer 7

After all of the wax layers are in place the insect produces wax that is secreted through pore canals

Question 8

What is the fifth step of molting?

Answer 8

The insect sheds its old cuticle

Question 9

What is the sixth step of molting?

Answer 9

The insect first escapes from the old cuticle, it is very white/pale and the insects are known to be teneral

Question 10

What is the seventh step of molting?

Answer 10

The insect must expand its body size while the new cuticle hardens and dries.

Question 11

Within insect eyes we have sensory cells, what are they called?

Answer 11

Rhabdomere

Question 12

What forms a rhabdom?

Answer 12

Usually two or more cells that are united to form an optic rod or rhabdom

Question 13

Rhabdoms are enclosed in single eye units called…

Answer 13

ommatidia (singular is ommatidium)

Question 14

What forms the eyes?

Answer 14

grouped together ommatidia

Question 15

In adults we have two types of eyes, what are they?

Answer 15

1. Simple eyes
2. Compound eyes

Question 16

Where are the simple eyes usually found in adults?

Answer 16

They are found dorsally (on top of the head) and are usually 3 in a triangle formation

Question 17

Where are the simple eyes usually found in larvae?

Answer 17

Usually are found more laterally and can be called stemmata or lateral ocelli.

Question 18

Simple eye function

Answer 18

Usually to discern night and day (light and dark)

Question 19

Make up of the simple eye?

Answer 19

Usually a large cornea that is transparent in order to admit light rays) it is made up of very few rhabdoms

Question 20

Compound eyes can have how many ommatidia?

Answer 20

Thousands, however the number can vary as dragonflies can have more than 25,000

Question 21

What can insects perceive with their eyes and what is this type of sight called?

Answer 21

They can perceive form, color, and movement. Their sight is compromised by the design of their eye which tends to portray objects as broken into smaller pieces (mosaic vision)

Question 22

Among compound-eyed insects the majority are… while some are…

Answer 22

1. Bichromatic
2. Trichromatic

Question 23

Can some insects detect ultraviolet light?

Answer 23

Yes, insects may have photoreceptors that detect ultraviolet light as many flowers reflect ultraviolet light