Insects feed on animals and plants in a variety of ways and their mouthparts have become modified for these purposes.
Mouth parts are essentially the paired appendages of mandibles and maxillary and labial segments of the head.
| Biting and Chewing | Most primitive and unspecialised type, which appeared in early insects in the course of evolution. e.g. Orthopteran insects like Grasshoppers, Cockroaches and crickets, larval forms like caterpillars of Lepidoptera. Maxillary Palps act as sensory feelers to locate the food. Lacinia are used for grasping, cutting, chewing. Mandibles masticate food with teeth like processes. Glossa and Paraglossa help in pushing the food into the mouth. | |
Piercing and Sucking | Mouth parts of insects that feed on fluids – modified in such a way that a tube is formed through which liquid can be drawn and saliva can be injected. e.g. Blood sucking insects like Mosquito, bed bug, Herbivirous insects like Aphids. Mandibles and Maxilla resemble fine needles, meant to pierce the skin or the plant tissue. Hollow and needle like hypo pharynx through which saliva flows. Labium forms a hollow grooved channel that encloses the needle like structures (mandibles, maxilla, hypo-pharynx). Labellae at the tip of Labium acts as feeler (sensory organs). | |
| Chewing and Lapping | Honey Bees and Bumble Bees. Long tongue formed from Glossa of the labium, ending in a spoon shaped labellum. Maxillary palp are very small. Temporary food channel is formed by the Proboscis, Galeae and Labial Palps fitting together. Through this, liquid food is sucked up, assisted by pumping action of the Pharynx. Labrum and Mandibles act for chewing. | |
| Sponging | Houseflies and other flies. Suck up liquefied food. Lack cutting weapons. Mandibles are absent. Maxillae are represented by 2 maxillary palps. Proboscis has 3 parts: -Rostrum bearing maxillary palps. -Haustellum serving as food passage. -Distal labellum, underside of which has pseudo trachea, all of which converge in the centre into the food groove. Food canal is formed by the labium, epipharynx and hypo pharynx lying in mid dorsal groove of the Haustellum. Labellum is used to lick by contractile activity. First collected into the Pseudotracheae and then passed on to the food canal. | |
| Siphoning | Butterflies and Moths are adapted for feeding on Nectar. Maxilla form the main proboscis instead of the labium. Mandibles and Labium are much reduced, maxillary palps are rudimentary. Galeae are elongated and coiled, each forming a half tube. When not in use, it is coiled into position below the head. |