Insect Mouthparts

diagram of insect mouthparts

In general, insect mouthparts are modified, paired appendages used to capture, manipulate and chew food (with the exception of the labrum, which is unpaired).

The labrum is a sclerite or plate that acts as the 'upper lip' in insects that have chewing mouthparts. It essentially forms the roof of the mouth and is useful for pulling food into the mouth. It moves longitudinally (i.e. an up and down motion) and is hinged to the clypeus.

The mandibles are the first pair of jaws in insects, moving laterally (i.e. from side to side) when in use. Mandible shape is strongly influenced by function and is therefore highly variable. For example a chewing insect will have strong tooth-shaped mandibles while in a sucking insect they will be thin and needle-shaped. Mandibles are used to cut, chew and tear food as well as to carry objects, fight and mould materials such as wax or soil.

The maxillae form the second pair of jaws and are located behind the mandibles. Maxillae are used for handling food and moves laterally much like the mandibles. Maxillae posses segmented palps and are structurally more complex than the mandibles.

The labium is a fused structure that forms the 'lower lip' or floor of the mouth in chewing insects. The labium is often regarded as the 'second maxilla' as it evolved from paired maxillae-like structures which are fused along the centre line. The labium moves longitudinally and possesses a pair of segmented palps. It is used to close the mouth from either below or behind, depending on its exact position.