Which statement correctly describes the hormonal regulation of insect metamorphosis and development?

Optimize your Entomology 1 PMT exam preparation with our targeted study material. Engage with our flashcards and multiple choice questions, complete with hints and detailed explanations. Get exam-ready today!

Multiple Choice

Which statement correctly describes the hormonal regulation of insect metamorphosis and development?

Metamorphosis in insects is controlled by two hormones working together: ecdysone and juvenile hormone (JH). Ecdysone is the signal that triggers molts, but the outcome of each molt depends on how much JH is present. When JH levels are high during a molt, the ecdysone cue leads to another larval instar. If JH levels are low or absent, the same molting signal pushes development toward metamorphosis—first to the pupal stage in holometabolous insects, and eventually to the adult. This interplay explains why simply having ecdysone isn’t enough to determine the fate of each molt; the presence or absence of JH determines whether the molt stays within the larval form or proceeds to pupation and eventual adult formation. Environmental cues can influence the timing of these hormonal changes, but the actual transitions hinge on JH levels in concert with ecdysone.

Metamorphosis in insects is controlled by two hormones working together: ecdysone and juvenile hormone (JH). Ecdysone is the signal that triggers molts, but the outcome of each molt depends on how much JH is present. When JH levels are high during a molt, the ecdysone cue leads to another larval instar. If JH levels are low or absent, the same molting signal pushes development toward metamorphosis—first to the pupal stage in holometabolous insects, and eventually to the adult.

This interplay explains why simply having ecdysone isn’t enough to determine the fate of each molt; the presence or absence of JH determines whether the molt stays within the larval form or proceeds to pupation and eventual adult formation. Environmental cues can influence the timing of these hormonal changes, but the actual transitions hinge on JH levels in concert with ecdysone.

More practice questions