EVERYDAY SCIENCE

Detailed explanation-1: -Both molting and metamorphosis are controlled by hormones. Molting is initiated when sensory receptors in the body wall detect that the internal soft tissues have filled the old exoskeleton and trigger production of a hormone from neurosecretory cells in the brain.

Detailed explanation-2: -Molting in insects is regulated by molting hormones (ecdysteroids). The major active hormone, 20-hydroxyecdysone, is formed by ecdysone 20-monooxygenase-catalyzed hydroxylation of ecdysone.

Detailed explanation-3: -Molting in crustacean is under the tight endocrine control of many hormones. Among those hormones, the steroid hormone ecdysone is the major hormone known to initiate the molting process (Claeys et al., 2006). Therefore, an increase of ecdysteroid titer in the hemolymph is needed for the start of the molting process.

Detailed explanation-4: -ecdysone, a hormone that initiates molting, which is the periodic shedding of the outer skeleton that typically occurs in insects and other arthropods.

Detailed explanation-5: -Insect molting and metamorphosis are controlled by two effector hormones: the steroid 20-hydroxyecdysone and the lipid juvenile hormone (JH) (Figure 18.21). 20-hydroxyecdysone initiates and coordinates each molt and regulates the changes in gene expression that occur during metamorphosis.