Metamorphosing - Insect Metamorphosis - Hormonal Control

Hormonal Control

Insect growth and metamorphosis are controlled by hormones synthesized by endocrine glands near the front of the body.

Neurosecretory cells in an insect's brain secrete a hormone, the prothoracicotropic hormone (PTTH) that activates prothoracic glands, which secrete a second hormone, usually Ecdysone (a ecdysteroid), that induces ecdysis.

PTTH also stimulates the corpora allata, a retrocerebral organ, to produce juvenile hormone (JH), which prevents the development of adult characteristics during ecdysis. In holometabolous insects, molts between larval instars have a high level of JH, the moult to the pupal stage has a low level of JH, and the final, or imaginal, molt has no JH present at all.

Read more about this topic:  Metamorphosing, Insect Metamorphosis

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