Insect Growth and Development

Question 1

What is molting?

Answer 1

Process of periodically shedding / renewing cuticle… (‘ecdysis’)

Question 2

What are the three steps of molting and how are they different?

Answer 2

1. Apolysis - cuticle separates from epidermis, epidermal cells divide, endocuticle reabsorbed.
2. Ecdysis - ‘shedding skin’, old cuticle breaks, insect emerges.
3. Sclerotization - rehardening, bursicon hormone

Question 3

What is shed during a molt?

Answer 3

Cuticle is shed during molt.

Question 4

What is the shed skin of an insect called?

Answer 4

Exuvia

Question 5

What color are most insects when they emerge from a molt?

Answer 5

White (haven’t sclerotized yet)

Question 6

What process is used to change color and harden the exoskeleton?

Answer 6

Polyphenols… “tanning” in taxidermy, controlled by bursicon hormone.

Question 7

What is the period between molts called?

Answer 7

Instars

Question 8

What two hormones control molting?

Which one is called the “molting hormone”?

Answer 8

Juvenile hormone (JH) and ecdysone.

Ecdysone is known as “molting hormone”.

Question 9

If JH is low, then…

Answer 9

… the insect would be an adult following the next molt.

Question 10

If JH is high, then…

Answer 10

… the insect would be immature following the next molt.

Question 11

What is voltinism?

Answer 11

Number of generations of an organism in a year.

Question 12

What is the difference between univoltine and multivoltine?

Answer 12

Univoltine - 1 per year (Japanese beetles)

Multivoltine - > 1 per year (aphids, chinch)

Question 13

Define diapause.

Answer 13

Hormonally controlled, physiological condition that controls dormancy.

Question 14

What is a diapause in cold weather?

Answer 14

Overwintering

Question 15

What is a diapause in warm weather?

Answer 15

Aestivation