Final answer:
Yes, a fall armyworm is classified as an insect. It shares the common characteristics of insects including body segmentation, legs, wings, and the ability to undergo metamorphosis. Insects have diverse ecological roles, can develop resistance to pests, and are crucial in ecosystems.
Step-by-step explanation:
The question asks whether a fall armyworm is an insect or not. Fall armyworms are indeed classified as insects. They belong to the Lepidoptera order, which encompasses moths and butterflies. Insects are characterized by having a body divided into a head, thorax, and abdomen, three pairs of legs, compound eyes, one pair of antennae, and typically one or two pairs of wings. Insects also undergo distinct life stages such as egg, larva, pupa, and adult in a process called metamorphosis. Examples of insects include mosquitoes (Aedes spp.), gypsy moth (Lymantria dispar dispar), and horse-chestnut leafminer (Cameraria ohridella).
Insects are incredibly diverse and play various ecological roles, including being pollinators for flowering plants, acting as natural pest control agents, and even engaging in complex social behaviors as seen in social insects like ants, bees, and wasps. In terms of pest control, for instance, they can develop resistance to biological controls like the Bt toxin through natural selection, which could explain the hypothesized resistance in purple-legged insects from the initial question.