Eristalis tenax (Linnaeus, 1758)
Biology & ecology:
The larva is of the ?long-tailed?, semi-aquatic type, living in organically enriched ooze such as the mud fringing eutrophic and/or polluted water bodies, the run-off from farmyard manure heaps, silage and slurry pits, and even exudates from putrefying corpses. When mature, larvae leave to look for somewhere dry, often a little above ground, to pupate. In doing so they may travel tens of metres from the larval habitat and turn up in unusual places. Adults disperse widely and visit a wide range of flowers. Can be abundant in gardens. Adults overwinter (not infrequently in houses), and occasional individuals can be seen during warm spells throughout the winter.
Widespread and very common but seemingly more coastal in northern counties of England and in Scotland. Markedly anthropogenic, a pronounced migrant and with a very long flight period.
Status & conservation:
Occurrence has increased over the past 35 years.