Predator-Prey Ecology of Dytiscids

Dytiscids are top invertebrate predators in most freshwater habitats, particularly in lentic systems such as wetlands and ponds. Adult and larval dytiscids are often considered to be generalists, feeding on zooplankton, aquatic macroinvertebrates, larval amphibians, and fish; however, some species selectively feed on certain prey types relative to others and many engage in cannibalism and intraguild predation. These predator-prey interactions cause a variety of consumptive and non-consumptive effects on prey abundance and community composition in freshwater habitats. Dytiscids are also notable predators of mosquito larvae and thus explored as biological agents for mosquito suppression, particularly in areas where mosquitoes are vectors of diseases and in northern areas. Dragonfly nymphs, fish, amphibians, reptiles, birds, and mammals are known predators of dytiscids, although the extent to which these organisms rely on dytiscids for food remains unclear. Given the prominent role of dytiscids in freshwater food webs, future research should be aimed at improving basic knowledge of dytiscid feeding ecology, using dytiscids to test predator-prey and trophic theory, describing the potential for dytiscids in conservation biological control, and examining how environmental change affects the role of dytiscids as predators of vector and nuisance species.