In gradual metamorphosis, what happens during the growth stages called instars?

• A. They molt and each time the insect takes on an aspect of the mature form.
• B. They immediately become winged adults.
• C. They do not molt after hatching.
• D. They pupate and remain unchanged.

Answer: (A)

In gradual metamorphosis, growth happens through molts called instars, and there is no pupal stage. The immature insects (nymphs) look like smaller versions of the adult and become more like the adult with each molt. With each instar, the insect sheds its skin and adds more adult features, such as body proportion and, in species that develop wings, wing development progresses across molts rather than appearing all at once. So the growth during instars is defined by molting and gradually taking on the mature form.

That’s why the correct idea is that they molt and each time they take on an aspect of the mature form. The other options don’t fit: they don’t become winged adults immediately after hatching, they do molt after hatching, and there is no pupation or pupal stage in gradual metamorphosis. In forestry pests like aphids or leafhoppers, you’d see this stepwise, increasingly adult appearance across several molts rather than a single leap to an adult form.