The last instar larva usually leaves the water to find a pupation site. Adults emerge and walk or fly to the water. Adults may stridulate to attract mates. Eggs are usually laid in the habitat of the larvae and seldom diapause. All trophic roles are assumed by Coleoptera species.
Many species are predacious, some with extra-oral digestion.
Species from secondarily aquatic families often feed on aquatic vascular plants. Communities Coleoptera species are present in streams of all sizes as well as all types of shallow lentic habitats. The larvae and adults of most species are dependent on atmospheric oxygen, but some respire aquatically or obtain oxygen from submerged vascular plants. Beetle communities are most complex in small, warm, ponds, where the many species are separated by habitat, trophic role, period of activity, and body size. Temporary ponds are often well populated.