The Highland Biological Recording Group

The Sericomyia hoverflies

The two species of hoverfly Sericomyia silentis and S. lappona are common in Highland and are easily identified in the field. S. silentis in particular, with its black and yellow stripes, is a convincing mimic of a social wasp when in flight - less so when at rest, but still sufficently wasp-like to panic people who are that way inclined.

Pictures can be found on the websites listed on the syrphids page. Both are large, broad-bodied flies, silentis larger than lappona. S. silentis appears black and yellow; lappona rather dark with thin whitish stripes and a distinctive brown scutellum.

Distribution, habitat and phenology

The distribution (records from my database only) of the two species is shown in the maps. Both are widely distributed and found predominantly in moorland, heath or forest edge, but S. silentis especially is found frequently in gardens. There are records of both from the Western isles, Orkney and Shetland. They breed in boggy ground. The numbers give an idea of the difference in abundance of the forms.


30 records, 15 squares, 44 individuals	126 records, 78 squares, 256 individuals
Distribution of Sericomyia lappona (left) and S. silentis (right). The difference in distribution and abundance may be exaggerated, as recording effort was generally much higher when S. silentis was active than earlier in the year. Maps created with DMAP.
	The phenology of the two Sericomyia species. S. lappona (blue) is distinctly earlier than silentis, though both can be found together. The apparent very large peak of S. silentis in July may be an artefact, as recording effort was generally much higher in that month.

Food plants recorded for Sericomyia silentis in the north and west of Scotland. Bramble Rubus fruticosus and thistles Cirsium spp. - especially Marsh Thistle C. palustre - form half the food records in the sample (N=77). S. lappona was seen at a variety of plants, none obviously more frequently than others (N=11).

Records

Any records of S. lappona, and records of silentis from the Hebrides, Orkney or Shetland can be reported initially by email giving date, place, six-figure grid reference and any other relevant details. Photographs can be used to confirm identification.