Which of the following insects is classified as a sucking insect?

The correct answer is an aphid, as aphids are well-known for their feeding behavior, which involves piercing plant tissues and sucking out the sap. This feeding method is characteristic of sucking insects, which typically have specialized mouthparts designed for this purpose. Aphids can transmit plant viruses, making them significant in agricultural settings.

In contrast, maggots (the larval stage of flies) primarily feed on decaying organic matter and do not possess sucking mouthparts. Thrips, while they do feed by rasping and sucking, are distinct from true sucking insects like aphids because they have different mouthpart structures and feeding behaviors. Beetles, on the other hand, are chewing insects and do not suck fluids; they use their mandibles to bite and chew plant material. Understanding these classifications helps in managing pest populations effectively in plant science.