This black and yellow banded wasp is very similar to Symmorphus crassicornis and expert help is needed with identification.

Adults seem to prefer damp places, often near streams and ditches and their flight paths are associated with patches of foliage in full sunlight.

Adults of S. gracilis are most likely to be found during June and July, but also at the end of May and sometimes during August.

It hunts for larvae of the chrysomelid beetle Chrysomela populi and, in addition, Cionus hortulanus, a weevil associated with figwort.

Widespread in southern England, and north to Yorkshire.

Status in Leicestershire and Rutland not known.