Life Cycle Eggs may hatch quickly or undergo long periods of diapause. The first instar of some lentic species is planktonic. Most aquatic Diptera species have 3 or 4 larval instars. Pupation of most of the fully aquatic species occurs underwater, the more semiaquatic species may pupate above water. The pupae may swim to the surface before the adult emerges or it may remain on the bottom.
Most species are univoltine or multivoltine, but a some are semivoltine.
Adults are terrestrial, mostly short lived, and they may or may not feed before mating. Many have mating swarms. Some species are parthenogenetic. Eggs are laid in or near the water. Trophic Roles Larvae assume all trophic roles- scrapers, collectors, shredders, and predators are well represented, some are plant miners and parasitoids.