What insect is commonly associated with piercing-sucking mouthparts?

Mosquitoes are commonly associated with piercing-sucking mouthparts primarily because of their feeding behavior. The mouthparts of mosquitoes are specialized for penetrating the skin of their hosts to access blood, which provides essential nutrients. This adaptation is crucial for their reproduction, as female mosquitoes require blood to develop their eggs. The structure of their mouthparts includes a long proboscis that allows them to efficiently pierce the skin and suck blood, distinguishing them from other insects that do not possess this capability.

In contrast, beetles generally have chewing mouthparts suited for grinding and tearing food rather than piercing. Dragonflies are also primarily predatory and have mouthparts adapted for capturing and consuming prey rather than sucking. Cockroaches possess mouthparts designed for chewing and scraping, which are more suited for their omnivorous diet. Therefore, the unique adaptation of mosquitoes' mouthparts for piercing and sucking makes them the correct choice for this question.