Parasyrphus nigritarsis (Zetterstedt, 1843)Nomenclature
Syrphus nigritarsis Zetterstedt in Coe (1953).Biology
The larva is predaceous upon the larvae of Chrysomelid beetles on Alder Alnus glutinosa (Chrysomela aenea) sallows Salix sp. (Lochmaea capraea) and Dock Rumex (Gastrophysa viridula). These generally occur in the vicinity of sallows and Alder along sandy banks of rivers and streams. Adults visit umbellifer flowers and may also be found sun-basking on leaves.Distribution
This is mainly a northern and western species that is widely distributed across Scotland, Cumbria and Wales, but is also reported from East Anglia, South Hampshire and Cornwall. Since its larval requirements have been better understood, it has been recorded much more frequently and is now known to be more widespread and frequent than was previously thought.Status
Lower Risk (Nationally scarce) - Ball & Morris, 2010. Endangered (RDB1) - Falk, 1991 and Shirt, 1987.