Bee fly, Bombylius major, a bumblebee mimic feeding in my wildlife garden
This large bee fly looks like a dark-edged specimen, Bombylius major, one of only four species in Britain. It looks rather innocent as it feeds upon the nectar from your garden flowers. It has a dark secret though! You may see it in your garden from early spring. It forages on primroses as well as the flowers shown in the video.
It is a parasitoid and seeks out bumblebee and mining solitary bee nests and either lays its eggs near the entrance or flicks them on the off-chance that some of them will enter the bee’s nest entrance tunnel. I suppose this is a health and safety issue for it! A strong case of self preservation as to go near an insect that will defend its nest with jaws and a sting when you do not have a sting or jaws is rather risky! After hatching, the small maggot like larvae, crawl into the nest where they remain inactive until their chosen host larvae are about to pupate. Then they attach themselves and suck the life force, i.e. body juices, out of them. Quite grim really!
The next video is a slow motion film of a bee fly actually laying eggs in slow motion. Difficult to see but shows how quick they are at flicking/laying their eggs in a suitable nest site area at a safe distance!
For a really interesting and informative web site article with photos about bee flies with thanks to Dr. Africa Gomez who kindly allowed me to show the egg laying video.
For more information by the Natural History Museum click here