Dark-edged bee-fly

 

Saw the first dark-edged bee-flies Bombylius major in the garden at the beginning of this week, feeding on lesser celandine nectar. These cheerful little spring flowers have spread all over the garden and I gave up trying to control them long ago, as their nectar supplies quite a few early-emerging insects, including bees, butterflies and hoverflies. 

The agility of hyperactive bee-flies is wonderful to watch. They rarely settle for more than a minute or two. The image below shows a curious feature of the rigid proboscis, which is three-pronged at the tip - I imagine there is a protective outer sheath surrounding the long inner tongue.

Bee-flies parasitize the nesting tunnels of mining bees, laying their eggs in flight in the mouth of the tunnel. When they hatch they feed on the grub of the bee host. Unfortunate for the host, but the bee-flies presence must be a sign of a healthy mining bee population in the garden.