[Campbell Biology P.1056] What is the role of juvenile hormone JH in determining whether ecdy... | Practice Question

What is the role of juvenile hormone JH in determining whether ecdysteroid induces molting or metamorphosis in insect larvae?

  • A: High JH levels cause ecdysteroid to stimulate molting, maintaining the larval state.
  • B: Low JH levels cause ecdysteroid to stimulate molting, leading to pupa formation.
  • C: JH directly inhibits ecdysteroid, preventing both molting and metamorphosis.
  • D: JH levels are irrelevant; ecdysteroid alone determines the process based on environmental cues.

Explanation

Juvenile hormone JH plays a crucial role in insect development by modulating the effect of ecdysteroid. When JH levels are high, ecdysteroid stimulates molting, allowing the insect to grow while maintaining its larval form. Conversely, when JH levels drop, ecdysteroid triggers metamorphosis, leading to pupa formation and subsequent transformation into an adult.