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 a biologic failure, What is A biologic Failure A biologic Fail...

What is A biologic Failure A biologic Failure can be defined as the inadequacy of the host to establish or to maintain osseointegration. The inability to establish osseoint

Human skeleton, what are the main coponents of human skeleton?

what are the main coponents of human skeleton?

What is the relationship between enzyme, Q. What is the relationship betwee...

Q. What is the relationship between enzyme and vitamins cofactors? Many vitamins are enzyme cofactors that cannot be synthesized by the organism and must be acquired from the d

Define prevention of idd - iodized salt distribution, Define Prevention of ...

Define Prevention of IDD - Iodized salt distribution? Many approaches to reduce iodine deficiency has been formulated. Some of these are reviewed herewith: Iodized salt dist

First type of rheological model, Q. First type of rheological model? Th...

Q. First type of rheological model? This method establishes relation between the pressure gradient and the volume rate of flow. Here, the piston measurement is used to measure

Antinutritional factors, Antinutritional factors Unconventional feed resou...

Antinutritional factors Unconventional feed resources including many agriculture by-products are rich in  antinutrients and toxic constituents, and tannins being the most widely o

Metameric segment - segmentation, Metameric segment - Segmentation On ...

Metameric segment - Segmentation On the other hand true metameric segment as best observed in annelids has separate schizocoelic body cavity of mesodermal origin in each segme

Define factors that are involved in the regulation, Describe the factors th...

Describe the factors that are involved in the regulation of respiration in a child who decides to hold his/her breath for as long as possible.

How much dna is in each stage, In meiosis - starting from stage G1 through ...

In meiosis - starting from stage G1 through the completion of meiosis, how much DNA is in each stage/phase when referring to the nucleus of spermatagonia?

Role of private sector in health care, Role of Private Sector in Health Car...

Role of Private Sector in Health Care One of the biggest policy challenges for the government is to decide on the appropriate areas and a suitable policy framework for having

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