Platycheirus perpallidus (Verrall, 1901)
Biology & ecology:
This is a wetland species that occurs along the margins of ditches, ponds and mires, especially where sedges Carex sp. occur in poor fen. The larva is predaceous upon the sedge aphid Trichocallis cyperi; there are also records of associations with the aphids Hyalopterus pruni on Lesser Reedmace Typha angustifolia and Subsaltusaphis rosseri on the sedge Carex rostrata. Adults seem to prefer the water-side edge of wetland vegetation.
This is mainly a northern and upland species that is widely distributed across Scotland and northern England, extending into Wales down to the Severn Estuary. There are no recent records south of the West Midlands, so the reduction in range appears to represent a retreat northwards. The single record from South Wiltshire in 1949 needs to be treated with caution!
Status & conservation:
In common with other wetland species, P. perpallidus appears to have undergone a decline.