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Unformatted text preview: Unit 4 - Integument, Development & Reproduction
1. Describe the three layers of an insect's integument.
2. Describe the advantages and disadvantages of an exoskeleton.
3. Using the proper terms for the structures involved, explain the steps in the molting
4. Explain the role of JH and Ecdysone, where they come from, and how they are used
together during the molting process.
5. Identify the internal and external reproductive structures of insects and describe what
they do or are used for. Introduction
Which layers make up the exoskeleton?
epicuticle, exocuticle, endocuticle What is the epicuticle made of?
lipids and polyphenols What is the exocuticle made of? How do these two compounds interact?
chitin-protein microﬁbers linked together to form plastic-like material Which layer of the exoskeleton is flexible but still contains protein and chitin?
endocuticle Which layer is waterproof? What makes it waterproof?
top layer, epicuticle. lipids are hydrophobic Which layer is cellular?
epidermis, below the cuticle. (replaces old exoskeleton after molting Which layers make up the integument?
cuticle, epidermis, basement membrane below integument What is the function of the basement membrane?
separates epidermal cells from insect blood, has pores large enough to allow proteins in the blood to pass through
to epidermal cells Exoskeleton advantages
What are three functions (or advantages) of the exoskeleton? 1. physical barrier to protect insect
2. waterproof barrier keeping in body moisture in dry habitats, keep water out of wet
3. place for muscles to attach since insects lack an internal skeleton Disadvantages
What are the disadvantages to having an exoskeleton?
limits size of insect- organs and muscles grow inside exoskeleton, pressure will eventually break the cuticle
exoskeleton must shed in order for growth to continue 1. Apolysis-- cuticle separates from epidermal cells.
2. Epidermal cells secrete molting ﬂ uid w/ enzymes to breakdown old cuticle. Material from the broken down exoskeleton is recycled
Name and describe the four molting steps:
t o form part of the new cuticle.
3. Epidermal cells secrete foundation for new cuticle &recycle parts of old cuticle. continually added to shove old cuticle up and
away. old cuticle will break from the pressure.
4. Ecdysis--insect will move its way out of old cuticle. The insect remain still until the new cuticle hardens. Molting hormones
Where is Juvenile Hormone secreted from?
Where is ecdysone secreted from? copora allata (part of the brain) tiny pair of glandsnear thoracic spiracles What is the function of JH in the larval stage?
What is its function in the adult stage?
What is the function of ecdysone? keeps the insect a juvenile aids in egg production, stimulates accessory glands in the male stimulates cells to secrete products that will form a pupal exoskeleton When JH levels drop, and the insect is ready to molt, what kind of cuticle is formed?
pupal exoskeleton JH analogs or mimics - Journal Entry
Fill in the names of the insect reproductive organs:
1.) paired ovaries
2.) lateral oviduct
3.) spermathecal gland
3.) accessory gland
4.) ejaculatory duct
Why do you think a female insect does not have a uterus? ASSIGNMENT Reproductive Organ Functions
List the functions of the following reproductive organs.
aedeagus: copulatory organ, variably construced (penis)
accessory gland: gland opening to genital chamber testis: male gonads
vas deferens: ducts that carry sperm from testes
seminal vesicle: sperm storage organ
ejaculatory duct: duct from vas deferens to gonopore
ovary:empties mature eggs (oocytes) to later oviduct via calcyes
ovarioles: ovarian tubes that form the ovary (germarium, vitellarium, pedicel) lateral oviduct: paired tubes uniting to form common oviduct spermatheca: receptacle for sperm deposited during mating (stored until needed for fertilization)
oviduct: transport eggs accessory glands: gland opening to genital chamber spermatheca:
common oviduct: tubes leading from fused lateral oviducts to vagina ...
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This note was uploaded on 12/16/2011 for the course ENY 3005 taught by Professor Staff during the Summer '08 term at University of Florida.
- Summer '08