Integument Structure and Function

1) What advantages and disadvantages does having an exoskeleton provide?

2) How do the juveniles and adults of the following types of insects differ from one another, and what stages does each go through? Which ones continue to molt after adulthood and which do not? Why?

Ametabolous

Hemimetabolous

Holometabolous

3) Explain the difference between a stadium and an instar? In your answer, define ecdysis and apolysis.

Klowden Figure 2.3

4) Draw a cross section of insect integument including each of the following structures and explain what each one is/does:

Basement membrane

Epidermis

Epidermal cells

Sensory receptors

Oenocytes

Procuticle

Endocuticle

Exocuticle

Epicuticle

Wax layer

Cement

Pore canal

5) Draw and label two adjoining epidermal cells, including each of the following structures, and explain the function of each:

adhering zonule

gap junctions

hemidesmosomes

6) Explain the function of each of the following integument modifications:

Arthrodial membrane/ intersegmental membrane

Ecdysial lines

Reflexive bleeding

Pore canals

7) What are the general functions of proteins and chitin? Where are they synthesized? Describe how hydrogen bonds and the arrangement and orientation of chitin result in the strength of the cuticle.

8) How do the following protein types change the character of the cuticle?

Resilin

Hydrophobic, positively charged proteins

Acidic proteins that bind more water

9) Where are lipids primarily found? What are their major functions?

10) What is sclerotization? What is the purpose of sclerotization? What hormones regulate sclerotization?