Cheilosia cynocephala Loew, 1840
Biology & ecology:
The larva tunnels the stems of Musk Thistles Carduus nutans but an association with Welted Thistle C. crispus has also been noted in Warwickshire. Adults are usually found in unimproved calcareous grassland where the larval food plant occurs, often near rivers, streams or flushes. Adults fly low amongst the vegetation and visit a range of flowers including white umbels and yellow composites.
The distribution of this species mainly follows the Chalk and limestone from East Anglia to the Mendips. Records are somewhat concentrated towards the south-west (Dorset, Somerset & Wiltshire), with few records from the chalk of south-east England, despite this being a relatively well-recorded area. There are thinly scattered records from Wales and northern England, and two localities in Scotland, near Edinburgh.
Status & conservation:
There has been some decline in occurrence since 1985. This may be an artefact of recorder effort because relatively few modern recorders report the Cheilosini and the data may be partially skewed as a result.