Cheilosia fraterna (Meigen, 1830)
Biology & ecology:
The larva tunnels the stems and basal rosettes of Marsh Thistle Cirsium palustre. Adults are often seen visiting flowers such as buttercups Ranunculus sp. in marshy places and damp meadows. According to Speight (2010) this is a woodland species found in clearings, often along streams or rivers with tall herb communities.
Although widely distributed and frequent, this species seems to be more abundant in the north and west. It is also considerably less common in the East Midlands. The specimen described as ?Cheilosia species C? of Stubbs & Falk (1983), seems to be a particularly small individual from the second generation of this species (Falk quoted in Stubbs, 1996).
Status & conservation:
There has been a noticeable decline in occurrence in most areas but a significant increase in the uplands and islands. The decline may to be an artefact of recorder effort because relatively few modern recorders report the Cheilosini and the data may be skewed as a result. Conversely, the rise may reflect recent efforts to ensure better coverage of uplands and northern regions.