Distribution: The species is widespread throughout Europe, the Middle East and up to Siberia (Cranston et al. 1987, Schaffner et al. 2001, Becker et al. 2003).

Habitat: Aquatic stages of Coquillettidia richiardii mostly develop in permanent stagnant water bodies; the breeding sites include the littoral of lakes and ponds, swamps, peat or oxbows, overgrown with submerse macrophytes or helophytes, such as Acorus, Carex, Glyceria, Nymphaea, Phragmites, Ranunculus, Sparganium and Typha (Shute 1933, Mohrig 1969, Guille 1976, Aspöck et al. 1970). Larvae and pupae live attached to the vegetation in a depth between 30 cm (Mohrig 1969) and more than one metre (Shute 1933). The water body must not dry up or freeze up during the larval phase (Mohrig 1969).

Biology: Eggs are laid in rafts on a free water surface and hatch at intervals up to about two weeks after oviposition; both larvae and pupae live permanently below the water surface and obtain oxygen by piercing the roots of submerged plants with their modified larval siphons or pupal trumpets (Guille 1976). The special lifestyle of the larvae reduces the risk of predation but handicaps nutrition; therefore larvae breed only in water rich in organic matter and suspended micro-organisms (Schaffner et al. 2001). Larvae may change their support, but pupal stages always remain on the same place, fixed by their respiratory trumpets; they leave their support only a few hours before imago emergence after breaking the pierced tips of the respiratory trumpets (Mohrig 1969, Schaffner et al. 2001).

Coquillettidia richiardii is univoltine (Service 1969a), but may show 2-3 generations in southern regions (Schaffner et al. 2001). First instar larvae are present from June to September, other instars may be found throughout the year; larvae develop slowly, though feeding throughout the winter and almost a year passes between oviposition and adult emergence (Shute 1933, Cranston et al. 1987). Hibernation exclusively takes place in the larval stage (Mohrig 1969). Pupae are found for a short period between May and July (Marshall 1938).

Adults: In Central Europe, imagoes hatch at the end of June and are present throughout the summer till September or October (Marshall 1938, Trpiš 1962, Mohrig 1969, Rettich et al. 1978, Aspöck et al. 1970).