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

Risk analysis - in-vitro studies, In-vitro studies Mechanistic  data mi...

In-vitro studies Mechanistic  data might be  supplemented by  data  from in-vitro  studies, like  as information on genotoxicity derived from reversion assays or other same ass

Explain capillaries of the vascular system, Q. What are the capillaries of ...

Q. What are the capillaries of the vascular system? Capillaries are small blood vessels that perform exchange of substances between the tissues and blood the body Capillaries a

Egestion, After the food intake is over, the food gets digested, assimilate...

After the food intake is over, the food gets digested, assimilated and finally egested through the kidneys and anus. The urinary system: • Filters waste materials from the blood

Floating stage - hydrarch, Floating Stage - Hydrarch The pond is now c...

Floating Stage - Hydrarch The pond is now colonised by plant species which are rooted in mud but their leaves reach water surface and float. These are species of Nelumbo, Nymp

Acid-base imbalances from appearing in the body, List and briefly describe ...

List and briefly describe the mechanisms that prevent acid-base imbalances from appearing in the body. In addition, indicate where each mechanism functions most significantly.

Define structural elements - biological functions of protein, Define Struct...

Define Structural Elements - Biological Functions of Proteins? Structural proteins are fibrous proteins. The well known of the fibrous proteins are possibly the keratins, which

Describe the important factors of hand washing, Describe the important fact...

Describe the important factors of Hand washing Hand washing is an important practice to follow before doing any procedure for the patient. The infection can be transferred

Implant exposure - implant surgery, Describe Implant exposure ? Sound su...

Describe Implant exposure ? Sound surgical principles to minimize the surgical exposure based on the access required should be employed. A series of surgical approaches to achie

What is the significance of the -r group, Q. What is the significance of th...

Q. What is the significance of the -R group (variable radical) in an amino acid molecule? The -R group, also known as lateral chain, is the variable part of the amino acid mole

Chances of clinical risks, A foreign DNA has to target a precise chromosoma...

A foreign DNA has to target a precise chromosomal site and integrate with the host DNA. Are the methods of gene therapy strong enough to produce desired expression without mistakes

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