Arthropod mouthparts

The mouthparts of arthropods have evolved into a number of forms, each adapted to a different style or mode of feeding.

In general, arthropods have mouthparts for cutting, chewing, piercing, sucking, shredding, siphoning, and filtering.

This article outlines the basic elements of four arthropod groups: insects, myriapods, crustaceans and chelicerates.

Unlike other mouthparts, the labrum is a single, fused plate (though it originally was—and embryonically is—two structures).

It serves to hold food in place during chewing by the mandibles and thus can simply be described as an upper lip.

Crustaceans comprise a number of classes, with various feeding modes supported by a range of adaptations to the mouthparts.

In general, however, crustaceans possess paired mandibles with opposing biting and grinding surfaces.

Both the mandibles and the maxillae have been variously modified in different crustacean groups for filter feeding with the use of setae.

Filter feeding may have developed in association with swimming, with early morphological adaptations occurring on the appendages of the body trunk.

Filtering appendages generate water currents that bring food items into reach for collection by setae.

In some spiders, the chelicerae have teeth, which are used to macerate prey items to assist digestion by secreted enzymes.

In sea spiders, the chelicerae (also known as chelifores) are short and chelate and are positioned on either side of the base of the proboscis or sometimes vestigial or absent.

Sea spiders possess a tubular proboscis forward from the body trunk, at the end of which is the opening to the mouth.