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Flashcards in The Exoskeleton And Metamorphis Deck (14)
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1

What do you say the cuticle is when it’s brown in colour?

Sclerotized

2

What is the exoskeleton made of?

Chitin, which is linked to a protein matrix giving tensile strength

3

Give an example of a ‘rubber-like’ cuticle and when it might be used

Resilin: it is like a mechanical spring when bent so is good after a large fluid intake (arthrodial membrane)

4

When does size gain occur in an insect?

At the moult

5

Give the four layers of cuticle secreted by the epidermal cells

Endocuticle
Exocuticle
Epicuticle
Wax layer

6

Give the stages of the moult cycle:

1. Apolysis (cuticle still present but not attached)
2. New epicuticle forms
3. New exocuticle forms
4. Ecdysis (cuticle is moulted)
= Expansion

7

What are holometabolous insects?

Endopterygotes where they have immature stages called larvae and have a pupal stage

8

What are hemimetabolous insects?

Extopterygote where they have immature stages called nymphs e.g locusts

9

What are ametabolous insects?

Apterygotes where they undergo gradual or no metamorphosis e.g silverfish

10

What part of the cuticle is sclerotized?

The exocuticle

11

What are the two hormones that determine whether an insect develops a larval, pupal or adult cuticle?

Juvenile hormone
Ecdysteroid

12

What hormone does an adult not have?

Juvenile hormone

13

What does the ecdysis triggering hormone cause the insect to do?

Causes the insect to perform a stereotyped behaviour to shed the old cuticle

14

Give the order of the 5 hormones that control ecdysis

PTTH: triggers ecdysteroid synthesis
Ecdysteroid
Juvenile hormone
Ecdysis triggering hormone
Eclosion hormone
=ECDYSIS