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

Find the magnitude and the direction of his initial velocity, After leaving...

After leaving the end of a ski ramp, a ski jumper lands downhill at a point that is displaced 66.2 m horizontally from the end of the ramp. His velocity, just before landing, is 18

What are rna polymerase subunits, Each of the three eukaryotic RNA polymera...

Each of the three eukaryotic RNA polymerases has more subunits or 12 and so these are big complex enzymes. The genes encoding some of the subunits of each  eukaryotic  enzyme  show

What is the physiological explanation for archaic method, In ancient Greece...

In ancient Greece the father of Medicine, Hypocrates, described a method of diagnosing diabetes mellitus by tasting the patient's urine. What is the physiological explanation for t

What, what are mendal low

what are mendal low

Define nutrition and sports - physical fitness of an athlete, Define Nutrit...

Define Nutrition and Sports - Physical Fitness of an athlete? The physical fitness and performance of an athlete is affected by both current and previous nutritional status. T

Epidemiological association between hemophilia and HIV, What is the epidemi...

What is the epidemiological association between hemophilia and HIV infection? As hemophilic patients need frequent transfusions of clotting factors (VIII or IX) they are more s

Explain adverse effects of famciclovir, Adverse Effects of Famciclovir ...

Adverse Effects of Famciclovir Famciclovir has been generally well tolerated. Headache, nausea and diarrhea have been reported. Like acyclovir, famciclovir has been associated

Describe lipoprotein, Q. Describe Lipoprotein? Ans. There is consi...

Q. Describe Lipoprotein? Ans. There is considerable current interest in this lipoprotein, which consists of LDL with an additional apoprotein-apoprotein (a) attached to it

What property of water helps, South Dakota and Oregon are at similar latitu...

South Dakota and Oregon are at similar latitudes, and yet, on average, Oregon has warmer winters and cooler summers than South Dakota does. What property of water helps account for

Why does thermal inversion increases air pollution, Why does thermal invers...

Why does thermal inversion increases air pollution? What harm can thermal inversion cause to humans? Thermal inversion confines at low altitude a layer of pollutants that would

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