The larvae of which insect is known for its beneficial role in pest control and features chewing mouthparts?

The larvae of dragonflies, known as dragonfly nymphs, are significant predators in aquatic environments and play a beneficial role in pest control. These nymphs possess chewing mouthparts, which allow them to effectively capture and consume a variety of prey, including mosquito larvae and other small aquatic insects. This predation helps to keep the populations of potential pest species in check, contributing to the ecological balance of their habitats.

In contrast, dung beetles, while beneficial for decomposing organic matter, do not have a larval stage that is primarily focused on pest control. Similarly, deer keds do not provide pest control benefits; they are parasitic flies that feed on the blood of mammals and have a different ecological role. Earwigs, while they can consume small pests, are generally not known for their significant role in pest control compared to the predatory effectiveness of dragonfly nymphs. Thus, dragonfly nymphs stand out as the correct choice due to their role as effective aquatic predators with chewing mouthparts.