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 suppuration, Suppuration High number of PMN cells have been det...

Suppuration High number of PMN cells have been detected around implants that are associated with severe signs of mucosal inflammation. Several studies have shown the presence o

Structures of a flowering plant, Which structures of a flowering plant give...

Which structures of a flowering plant give rise to (a) potatoes, (b) the fleshy scales of an onion?   (a) A potato is a tuber formed at the end of an underground stem (b) O

What is the difference between amnion and chorion, What is the difference b...

What is the difference between amnion and chorion? Amnion is the membrane that covers the embryo. Chorion is the membrane that covers the amnion, the yolk sac and the allantois

Define the elements that affects the fitness, Define the elements that affe...

Define the elements that affects the Fitness? Fitness varies from a person to person. It is influenced by age, sex, heredity, personal habits, exercise and eating practices. Th

Adverse effects of air pollution, Air pollution affects both living and non...

Air pollution affects both living and non-living matter. The effects can be classified as.

What is centrioles in cell structure, What is Centrioles in cell structure?...

What is Centrioles in cell structure? Most cells of higher organisms contain pairs of cylindrical bodies called centrioles, which help to organize microtubules in cell division

What is mendelian genetics, What is Mendelian Genetics? Mendelian Gene...

What is Mendelian Genetics? Mendelian Genetics :  In 1868, an Austrian monk, Gregor Mendel, first published the basics of a study we now call Mendelian genetics. Mendel obser

What is cytoskeleton, The  cytosolic  surface  of  the  erythrocyte   plasm...

The  cytosolic  surface  of  the  erythrocyte   plasma  membrane  is  covered  through  a network of peripheral membrane proteins which make up the cytoskeleton in the figure. The

Explain the before abutment connection - implant failures, Before Abutment ...

Before Abutment Connection There can be wound dehiscence, and the presence of signs of infection such as swelling, fistula, pain prior to stage to surgery. It is important t

How sequences of events occur to activate protein kinase a, When glucagon b...

When glucagon binds to it's receptor on a liver cell, which one of the following sequences of events occurs to activate protein kinase A? -activation of G protein, activation of

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