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 contact osteogenesis, Contact Osteogenesis In this the osteoge...

Contact Osteogenesis In this the osteogenic cells attach to the implant surface and the new (de novo) bone is formed on the implant surface first. The developing bone matrix c

Explain cartilaginous and the osseous tissue, Which type of tissue are the ...

Which type of tissue are the cartilaginous and the osseous tissue? The cartilaginous and the osseous tissues are considered connective tissues as they are tissues in which the

Define technique of paper chromatography, Define Technique of Paper chromat...

Define Technique of Paper chromatography? Paper chromatography is used as 1. Ascending, 2. Descending or 3. Horizontal technique (circular paper chromatography) It is De

Define general characters and classification of arthropoda, Define General ...

Define General Characters and Classification of Arthropoda? These are metamerically segmented animals with an exoskeleton of cuticle. Scliizocoelic coelom is much reduced and is

What is biological control, What is biological control? Biological cont...

What is biological control? Biological control is a natural process to control the size of animal, microorganism or plant populations. Biological control is based on the knowle

What is the significance of pronephric, What is the significance of Proneph...

What is the significance of Pronephric? The first, or ancestral, kidney that appears in the anterior part of the coelomic cavity and is connected to the archinephric duct. In a

Relation between fecundation and end of the meiotic process, Q. What is the...

Q. What is the relation between fecundation and the end of the meiotic process during oogenesis? The oocyte II only completes the second meiotic division (interrupted at metaph

What is the significance of magnesium for plants, What is the significance ...

What is the significance of magnesium for plants? What are the other main biological functions of magnesium? Magnesium is fundamentally significant for plants because it is par

Explain about glycemic index, Q. Explain about Glycemic Index? Although...

Q. Explain about Glycemic Index? Although the use of exchange lists is still popular for planning diabetic diets, it has been realized in recent years that in exchange lists th

Determine the objectives of economic evaluation, Determine the Objectives o...

Determine the Objectives of Economic Evaluation? There are two objectives of economic evaluation. These are: 1) To introduce resource consideration into analysis and to asse

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