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

Eye muscles, MUSCLES - In eye orbit, eye ball is fixed by 6 skeletal...

MUSCLES - In eye orbit, eye ball is fixed by 6 skeletal muscles attached to 3rd, 4th & 6th cranial nerves (motor). 4 - straight or recti muscles are present. 2 - oblique

Mode of nurition, What mode of nutrition did lizard exihbite

What mode of nutrition did lizard exihbite

Define myocardial infraction and stress testing, Q. Define Myocardial infra...

Q. Define Myocardial infraction and stress testing? Prediction of disease is one of the primary functions of stress testing. We would like to be able to predict in each patient

Explain the endosperm of angiosperms, How different are the endosperm of gy...

How different are the endosperm of gymnosperms and the endosperm of angiosperms? In gymnosperms the endosperm is haploid (n), it is known as primary endosperm. In angiosperm th

Difference between translation and transcription, Q. What is the difference...

Q. What is the difference between translation and transcription? Transcription is the name given to the formation of DNA molecules from an open DNA chain used as a template, Tr

Microfilaments - cytoskeletal structures, MICROFILAMENTS Discovered ...

MICROFILAMENTS Discovered by Pelvitz. These are smallest cell structure. These are non-living structures. These are solid structures, consists of actin protein (c

Mollusca, in molluscathe foot is used for (capturing locomotion or both

in molluscathe foot is used for (capturing locomotion or both

Food chain and types of food chain, In an ecosystem various trophic levels ...

In an ecosystem various trophic levels are interlinked with each through a food chain. ( the transfer of food energy from green plants through a series of organism with repeated ea

Hypoglycaemia unawareness, Hypoglycaemia Unawareness ? Some people ...

Hypoglycaemia Unawareness ? Some people with diabetes do not have early warning signs of low blood glucose, a condition called hypoglycemia unawareness. ? This conditio

What is fluorescent microscope, What is Fluorescent Microscope? In abo...

What is Fluorescent Microscope? In above said microscopes, image is produced from light that passes through a specimen. In fluorescent microscope, however, specimen image is f

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