Family Dytiscidae

Abstract

Dytiscidae (commonly known as "predaceous diving beetles") are the most speciose water beetle family, with over 4,400 known species. They are distributed world-wide, being more common in tropical and subtropical areas. In the neotropical region, more than 700 species in 60 genera, 23 tribes and 10 subfamilies are known. Dytiscids have a wide range of size and are well adapted to aquatic life, being considered as "true water beetles" since both adults and larvae are aquatic. They occur in almost all types of aquatic habitats, although they are much more common in lentic than lotic environments. In running waters, they are usually found in slow-flowing areas near the margins. Diving beetles are abundant on lake shores, ponds, pools, dams, wetlands, temporary streams and lagoons. Larvae and adults of several species can also be found in groundwater, seepages, and phytotelmata and few species are terrestrial. Dytiscids are aquatic in all stages except the pupa. Pupation usually occurs near the water, on wet soils or underground in cells built by the larvae. The newly hatched adults return to the water but retain their capacity to fly, which allows them to disperse from one water body to another, either to reproduce or when the conditions are adverse. Both larvae and adults are predaceous, feeding on insects, crustaceans, leeches, molluscs, tadpoles and small fish. In this chapter we present a brief outline of the ecology and systematics of diving beetles, and keys for the identification of the neotropical fauna.