Which type of mouthparts are primarily used by insects that feed on liquids?

Insects that feed on liquids typically possess specialized mouthparts that allow them to effectively pierce surfaces and suck up the fluid. The biting/piercing-sucking mouthparts are characterized by a structure that can puncture the skin or body of plants or animals. For example, many blood-feeding insects like mosquitoes use this type of mouthpart to penetrate their host's skin and access blood.

In contrast, sponging-lapping mouthparts are designed for liquid feeding as well but are more suitable for soaking up fluids rather than piercing. An example would be house flies, which rely on their sponging mouthparts to absorb liquids rather than inject or suck them out through a sharp structure. Chewing mouthparts are mainly adapted for grinding solid food, making them unsuitable for liquid feeding. Siphoning mouthparts, found in some butterflies and moths, are also designed for drinking liquids but in a different manner, involving a long proboscis that coils up to reach nectar in flowers.

Therefore, the mouthparts classified as biting/piercing-sucking are specifically adapted for the function of puncturing and extracting liquid from a host or substrate, making them the most appropriate choice for insects that primarily feed on liquids.