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

Define mechanism for copper absorption, Define Mechanism for Copper Absorpt...

Define Mechanism for Copper Absorption? As in the case of other minerals, copper absorption appears to occur by two mechanisms: i) Saturable active mechanism, which operates

Name mimicry by which insect mimics insec for protection, From the followin...

From the following, name the type of mimicry by which a palatable, acceptable insect mimics an unfavorable, noxious insec for protection. a) Batesian mimicry (pron: BATE-see-an

Composition of individual phase in phase diagram – one phase, Define Compos...

Define Composition of Individual Phase in Phase Diagram - One Phase? The way in which we interpret a two-dimensional phase diagram to obtain the compositions of individual phas

Adaptations to high wind velocity, Adaptations to high wind velocity Th...

Adaptations to high wind velocity The mechanical force of the wind and the grinding action of sand, dust, snow and other materials driven by it cause the plants to adapt themse

Explain about the dna viruses - carcinogenic, Explain about the DNA viruses...

Explain about the DNA viruses - Carcinogenic? The three DNA viruses found to cause human cancers are EBV, HBV and HPV. What are these? Let us find out. Epstein-Barr viru

After purchasing - nursing software, After Purchasing The following po...

After Purchasing The following points should be considered for after purchase facilities. Avail of any training the software engineer or vendor may provide, even if it

Endodermis , Endodermis is the layer of cells surrounding the vascular cyl...

Endodermis is the layer of cells surrounding the vascular cylinder of plants.

What are the main cellular functions of potassium, What are the main cellul...

What are the main cellular functions of potassium? Besides being significant for the osmotic regulation and for the acid-base equilibrium (pH) potassium is basic for the excita

Explain exotic species, Explain exotic species? Describe with the help ...

Explain exotic species? Describe with the help of two examples how the exotic species disturb the native species of an ecosystem ?

Inorganic and organic substances, Q. Living beings are made of inorganic an...

Q. Living beings are made of inorganic and organic substances. According to the molecular complexity how can each of those substances be classified? Inorganic substances, mole

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