Bee-Flies

The two Bee-Fly species that you are most likely to see. The less common Dotted Bee-Fly at the top and the fairly common Dark-edged Bee-Fly below.

It has been a brilliant spring so far for Bee-flies. Or, as my other half often says "I've just seen a Flybe in the garden"!) 

If you see what looks like a furry bee hovering in front of you and then, suddenly it has gone, it was probably not a bee at all, but a Bee-fly! 

Next time you come across one, especially if you should see it land, look more closely and you will notice its needle-like proboscis sticking out in front of it. Also, unlike bees, which have four wings, bee-flies have only two that they hold out at an acute angle when they settle.

Bee-flies are dependent on Solitary Bees. The female bee-fly hovers in front of suitable Solitary Bee ground burrows, darting forward and flicking her body rapidly downwards to release her eggs.

Although she lays hundreds of eggs, they weigh next to nothing and are at risk of not landing in the burrow itself.

However, the female Bee-Fly has a special technique to ensure this does not happen. She dips her abdomen onto the ground, collecting soil particles in a small chamber at the end of her abdomen. Then, as she lays each egg, it is coated in a fine layer of soil and dust, giving it the extra ballast to help it reach its target – the Solitary Bee’s tunnel.

If successful, the larva enters and locates a bee grub, and fastens on to it, gradually draining the bee of its fluids. The bee-fly larva spends winter in the bee’s chamber alongside the husk of its victim, emerging as an adult bee-fly the following spring.

Looking at the large number of Solitary Bees in my garden this year, the Bee-Fly population does not seem to be having an impact on its “host” species.

So, yet another amazing relationship taking place in my garden - and across thousands of other gardens across the country. See if you can find Bee-Flies in your garden, local park or nearby countryside!