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

Carbohydrate metabolism, CARBOHYDRATE METABOLISM Carbohydrates  are  br...

CARBOHYDRATE METABOLISM Carbohydrates  are  broken down into  monosaccharides which are absorbed into  the  blood stream.  In  the  liver and muscles, most  of  the glucose  is

Explain the mechanical requirements of implant materials, Mechanical requir...

Mechanical requirements of implant materials Dental implant s must be able to sustain and transfer loads -It should have adequate mechanical strength in order to distribute th

Hemoglobins - process of respiration, Hemoglobins - Process of Respiration ...

Hemoglobins - Process of Respiration Hemoglobins are the very well known of all respiratory pigments. The basic molecular unit of Hemoglobin contains a haem group bound to a

Downers cow syndrome, D o w n e r s cow syndrome The Downer's co...

D o w n e r s cow syndrome The Downer's cow, otherwise known as creepers, is commonly a fatal condition of dairy animal associated with the unsuccessful treatment of cas

Kuch, how vagina is inserted in cock

how vagina is inserted in cock

Biological species concept, Is the biological species concept subjective or...

Is the biological species concept subjective or objective? How about the phylogenetic species concept or is it subjective or objective?

How to reduce the toxicity of a chemical in the body, Which process may not...

Which process may not reduce the toxicity of a chemical in the body?

Explain the ethical decisions in nutrition care, Some of  the  situations  ...

Some of  the  situations  that  concern ethical decisions in nutrition care are as follows: Difficulty of adequate nutritional support of malnourished patients, a) A problem

Atelectasis and pneumonia - complications of cardiac surgery, Atelectasis a...

Atelectasis and Pneumonia Signs and symptoms are LV failure, hypovolemia, hypervolemia or renal vasoconstriction. Decreased breath sounds, poor ABG and poor cough reflex

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