Beetles

Code QC999999

See Key to Families of Australian Aquatic Coleoptera and Mecoptera Larvae

The Coleoptera is a diverse order of holometabolous insects with over 5,000 aquatic species (comprising, however, less than 2% of the world's described beetle species). About 10 families are exclusively aquatic as larva and adult, an additional few are predominantly aquatic as larvae and terrestrial as adults or vice versa , and several more have sporadic aquatic representation. Holometabolous; adult diagnostically with mesothoracic wings modified as rigid elytra; gaseous exchange usually by temporary or permanent air stores.

Larvae are very variable, all with distinct sclerotised head, strongly developed mandibles, 2-3 segmented antenna; 3 pairs of jointed thoracic legs, lacking abdominal prolegs; open peripneustic (9 pairs of spiracles) tracheal system, but variably reduced spiracle number in most aquatic larvae, some with lateral and/or ventral abdominal gills, sometimes hidden beneath terminal sternite. Pupation terrestrial (except some Psephenidae); pupa lacking functional mandibles.