Platycheirus immarginatus (Zetterstedt, 1849)
Biology & ecology:
The larva is predaceous on the aphid Trichocallis cyperi, although there are a variety of non British records relating to a range of other aphids that may actually relate to laboratory breeding projects. The adults occur within rank low vegetation and may be found visiting the flower heads of sedges Carex sp. and grasses in keeping with other related species. This is a wetland species that occurs in coastal grazing marshes, tidal rivers and other brackish marshes. Northern inland locations have a rich fringe of sedges on the banks of rivers and lakes.
The records, taken at face value, include many from inland locations. However, if only records based on males are accepted then it appears to be an entirely coastal species. It has been claimed to occur at inland localities, notably in the Spey Valley in Scotland, but we have yet to see a male specimen taken inland.
Status & conservation:
This is a difficult species to identify and our experience suggests that females cannot be reliably separated from those of P. perpallidus. There are over 300 records from 93 hectads in total, but only 27 of these state that they are based on males. The male records are from 20 hectads, 14 of which are dated since 1985. Only these male records are mapped.