Bee-flies are probably the most familiar of all the species covered by the recording scheme. One species in particular, the Dark-edged Bee-fly Bombylius major, is a familar sign of spring as it hovers over flowers and uses its long proboscis ('tongue') to feed from them.
But there are a number of other bee-fly species to look out for as well, and this page collects together some information about the group. If you see a bee-fly, please send in the record!
Join in with Bee-fly Watch 2017
Add your sightings (with a photo if you can) to iRecord or use the iRecord app and see how the 2017 bee-fly season progresses via our iRecord activity page (shows all the records for the common spring species, Dark-edged Bee-fly Bombylius major, plus any records of the three rarer species if they are recorded).
See a summary of the 2016 results in our newsletter.
For such cute, fluffy insects, bee-flies have a rather gruesome way of life! Bee-flies in the genus Bombylius lay their eggs into the nests of solitary mining bees. To do this (in at least some of the species) the adult females collect dust or sand at the tip of their abdomen, using it to coat their eggs, which is thought to provide camouflage and perhaps also add weight to them. Why do they want them to be heavier? Well, the female next proceeds to find areas of ground where solitary bees have made nest-burrows, hovering over the burrows to flick her egss into them (see video below). The added weight from the sand or dust may make it easier to flick the tiny eggs through the air into the burrows.
The bee-fly's larva hatches, crawls further into the bee burrows and waits for the bee's own larva to grow to almost full-size, at which point the bee-fly larva attacks the bee larva, feeding on its body fluids and eventually killing it. This is bad news for the bee of course, but bee-flies and bees have lived side-by-side for many millennia, and there is no evidence that bee-flies cause any major decline in bees.
For more detail on the bee-fly life-cycle see Louise Kulzer's account on the American "Scarabs" Bug Society, from which the above image of Bombylius larvae has been borrowed.
- Roy Kleukers' video of Dark-edged Bee-fly in the Netherlands, flicking its eggs into nesting burrows of the solitary bee Andrena vaga: