Interaction of insect hormones, Biology

Assignment Help:

Interaction of insect hormones in the process of metamorphosis

The organs and the hormones usually included in metamorphosis of insects. This is since despite the fact that there may be around 1 million dissimilar insect species, there is a striking similarity in the endocrine function of dissimilar hemimetabolous and holometabolous insects. Figure depicts a schematic outline of the interaction of hormones in the metamorphosis of insects. On the basis of figure let us study how the actions of the several hormones bring about metamorphosis in insects. The moulting process, the beginning of metamorphosis, is initiated in the brain. The stimulus may be neural, hormonal or environmental, and causes the neurosecretory cells of the brain to release the activation hormone that after synthesis changes into the active hormone known as prothoracic opic hormone (PTTH). The PTTH stimulates the prothoracic gland to generate ecdysone.

Ecdysone after being transformed into its active form, the ecdysterone, stimulates growth and causes the epidermis to secrete a new cuticle, start the moulting process. The ecdysterone further stimulates the epidermal cells to synthesize enzymes which digest and recycle the components of the cuticle. As long as the juvenile hormone is present, the ecdysone-stimulated moult results in a new larval instar. In the last larval instar stage, the synthesis of juvenile hormone is decreased, causing its levels to drop below a critical threshold value. This again triggers the release of PTTH from the brain. The PTTH in turn, stimulates the prothoracic gland to secrete not usually large quantity of ecdysone. The resultant ecdysterone, in the relative scarcity of JH, causes the instar to pupate. In other word the occurrence of the subsequent moult in the larva in the relative scarcity of JH and abundance of ecdysone, shifts the organism from larva to pupa. Throughout the period of pupation the corpora allata do not release any juvenile hormone and the ecdysterone stimulates the pupa to metamorphoses into the adult insect.


Related Discussions:- Interaction of insect hormones

Cardiac veins, Cardiac Veins The anterior cardiac consisting of vesse...

Cardiac Veins The anterior cardiac consisting of vessels covering the anterior right ventricle, I drain into the right atrium. The great cardiac vein drains the blood form

What do the major organs of the digestive system do, What do the major orga...

What do the major organs of the digestive system do? They are salivary glands, teeth, tongue, gums, esophagus, stomach, small intestine, large intestine, pancreas, liver, and g

What would happen to a cell, What would happen to a cell if it was placed i...

What would happen to a cell if it was placed into a hypertonic solution? Into a hypotonic solution? What would happen to a cell if the cell itself was hypertonic to the solution?

Learning objectives of gastrointestinal disease, Q. Learning objectives of ...

Q. Learning objectives of gastrointestinal disease? • explain the disease conditions, causes, complications of the disorders of the gastrointestinal tract, • discuss the ef

Explain the method of recombination or crossing-over, The method of recombi...

The method of recombination or crossing-over Which of the following is a false statement regarding the method of recombination or crossing-over? A. Crossing-over takes place

What is the life cycle of the gymnosperms, What is the life cycle of the gy...

What is the life cycle of the gymnosperms? As all plants they show a diplobiontic life cycle, i.e., alternation of generations with diploid and haploid stages. The lasting (fin

Cerebrum, what term is used to indicate its grooves?

what term is used to indicate its grooves?

Importance of nutritional interaction, Importance  of nutritional interact...

Importance  of nutritional interaction :- Now  being  realized.  Some  nutrients  are antagonistic to each other whereas others act synergistically. Examples of uniquely related

Estrogens, Normal 0 false false false EN-IN X-NONE ...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd