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

What is calvin cycle, What is Calvin Cycle? The dark reactions of photo...

What is Calvin Cycle? The dark reactions of photosynthesis are also known as the Calvin cycle. This process synthesizes glucose molecules using carbon dioxide from the atmosphe

Cardiac muscles, Normal 0 false false false EN-IN X-N...

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

What is selective waste collection, Q. What is selective waste collection? ...

Q. What is selective waste collection? The Recyclable waste is waste that can be reprocessed and used again. The waste recycling depends on the separation of the recyclable res

Reactants of photosynthesis, what are the reactants and the products of pho...

what are the reactants and the products of photosynthesis? under the thylakoid, stroma,and combined

Asexual reproduction and cloning in plants, before stem cuttings are plante...

before stem cuttings are planted the cut end of the stem is often dipped in a hormone powder .what is the point of this?

Symptoms of hiatus hernia, Q. Symptoms of hiatus hernia? In most patien...

Q. Symptoms of hiatus hernia? In most patients, no symptoms are seen. When symptoms do occur, they are: 1. discomfort after heavy meal, 2. Difficulty in breathing while l

Describe the term - near-far problem, Describe the term - Near-far problem ...

Describe the term - Near-far problem Signals closer to the receiver are received with less attenuation than signals farther away. Given the lack of complete orthogonality, the

What are proteins and why they are important for us, What are Proteins and ...

What are Proteins and Why they are important for us? We just read that proteins are essential for maintaining and sustaining life. What are proteins or what constitutes protein

Define nutrition management and feeding the premature infant, Define Nutrit...

Define Nutrition Management and Feeding the Premature Infant There are numerous nutritional risk factors in premature infants. These include: Elevated metabolic rate, th

Explain horizontal full mucoperiosteal flaps, Explain Horizontal Full Mucop...

Explain Horizontal Full Mucoperiosteal Flaps - Endodontic Surgery      a) Also called:  Envelope flap, b) Only a Horizontal incision, without the vertical releasing incision

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