Episyrphus balteatus (De Geer, 1776)
Syrphus balteatus De Geer in Coe (1953).
Biology & ecology:
The larva preys on a wide range of aphid species on trees, shrubs and herbs, including cereal crops, but seems to prefer aphid colonies low down. Adults are regular flower visitors and bask on sun-lit foliage. They are very frequent in urban areas, sometimes in considerable numbers.
This species migrates north from southern Europe in the spring, breeding along the way. Migrants typically arrive in Britain in late June and July when aphid numbers are building up, and larvae can reach high densities in cereal crops, resulting in vast numbers of emerging adults in late summer. Some adults overwinter here and winter records are not unusual. The recording scheme has received more records of this species than any other, although numbers vary hugely from year to year.
Status & conservation:
There has been an increase in occurrence over the past 35 years. This may partially stem from changes in the habits of recorders, with far more casual records reaching the recording scheme through website trawls and photographic recording, but the extent of the increase is too great for this to be the only explanation.