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 are respiratory pigments, Q. What are respiratory pigments? What is th...

Q. What are respiratory pigments? What is the respiratory pigment present in some arthropods? Which is the analogous molecule in humans? Respiratory pigments are molecules able

What is risk scoring, What is Risk scoring ? Risk scoring is an instrum...

What is Risk scoring ? Risk scoring is an instrument to assess both the relative risk as well as the absolute risk of developing Cardio-vascular disease and mortality in an ind

Illustrate production of red blood cells, Q. What is the substance that sti...

Q. What is the substance that stimulates the production of red blood cells? Which is the organ that secretes it? Under what conditions does this secretion increase? The substan

Identifications of a deficit by neuropsychological tests, Identifications o...

Identifications of a deficit by neuropsychological tests Ideometric approach and psychometric approach are the two methods that are used in the identification of deficits by ne

Show classification of englearn dprantls system, Q. Show Classification of ...

Q. Show Classification of englearn dPrantls system? The outline and basis of classification of englearn d Prantl's system are given below: 1) Plant Kingdom has been divided,

Mechanical valves, Mechanical Valves They are made of a combination o...

Mechanical Valves They are made of a combination of metal alloys, pyrolite carbon and dacron. Types of Mechanical Valves Caged-ball Valve (Star-Edwards) A me

Define surface sampling, Define Surface Sampling Food contact surfaces ...

Define Surface Sampling Food contact surfaces (e.g. storage tank, packaging material, ripening room, utensils, equipments, refrigerators etc.) which directly or indirectly (wal

How do birds reproduce, How do birds reproduce? Birds, like each verteb...

How do birds reproduce? Birds, like each vertebrate, have sexual reproduction. Their embryos develop within shelled eggs having extraembryonic membranes and outside the mother'

Some common air pollutants: ground level ozone, Ground level ozone: Grou...

Ground level ozone: Ground level ozone is the ozone present at the lower level of earth atmosphere. It is not emitted directly into the environment but produced by complex chemi

Parts of a typical flower with all its definations , parts of a typical fl...

parts of a typical flower? define its parts and internal parts completely? show complete colourful diagram?

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