Join the search for the year's first bee-flies

Bee-fly by Sue Taylor

BBOWT volunteer recorder, Sue Taylor takes a closer look some of the first insects of the year, distinctly furry little flies

When you see a bee-fly you know spring has finally sprung and life is hotting up! Depending on the weather, they can fly anytime from late February and there is one species that will be on the wing until September.

Every spring there is a light-hearted competition to see who will be the first to see a bee-fly, part of ‘Bee-fly Watch’ a national monitoring scheme run by the Soldierflies and Allies Recording Scheme.

The idea is to gather records of this rather cute, distinctively furry little fly, so that we can see how the weather, climate change and other factors such as habitat loss might affect where and when it can be seen.

Dark edged bee-fly

Dark edged bee-fly in flight taking nectar by Sue Taylor

You have almost certainly seen a bee-fly in your garden, though you may not have realised what it was, as many people mistake them for bees.

If you do see one, please take a photo, take a note of where and when you saw it and add your records to iRecord for the Soldierflies and Allies Recording Scheme. More information and identification guides can be found at Bee-fly Watch.

The most widespread bee-fly and the first to be seen each year is the dark edged bee-fly Bombylius major.  When it settles you can see that it has a marvellously furry little body with wings held swept back in a delta shape, the front edge of each wing is marked by a wide wavy edged black band.

In flight the dark wing marking cannot be seen, but the furry body and long needle like black proboscis (the tongue which it uses to sup nectar from flowers) can still be seen.

Dark edged bee-fly

Dark edged bee-fly showing the wavy dark edge and the long straight proboscis. Photo by Sue Taylor

With all that fur a bee-fly is an excellent pollinator, but it is not as innocent as it looks. Although the adult lives off nectar, its larvae live in the nests of solitary bees where they slowly eat the bee larvae ultimately killing them.

Their ‘hosts’, the solitary bees, nest in small tunnels dug into the ground. Somehow the bee-fly needs to get its egg into the tunnel. Watching them doing this is fascinating, the female fly gathers up dust onto the end of its abdomen coating her eggs in the dust. The eggs are now heavy enough that they can be flicked into the tunnel entrance, you can watch the bee-flies hovering and darting forward to flick the eggs in.

Dotted bee-fly

Dotted bee-fly named for the dark marks where wing veins meet. Seen March to June. Photo by Sue Taylor

We have two other species you might see, the dotted bee-fly whose clear wings have black dots where the veins cross and the downland villa which has shorter fur and stripes across its abdomen.

(Berkshire also has a fourth very rare species the mottled bee-fly which you are unlikely to see, now that is a challenge for anyone near BBOWT’s Wildmoor Heath!).

Downland Villa

Downland villa, look out for it on umbellifer flowers from June to September. Photo by Sue Taylor

The downland villa used to be incredibly rare but it is now spreading through suitable habitat, and although not common it is no longer rare. Warburg Nature Reserve and Dancersend are good places to find it. The host species on which its larvae feed is unknown but it may use moth caterpillars rather than solitary bees.

I’ve only ever seen the dotted bee-fly at College Lake, though it is relatively widespread and has been seen in gardens by some lucky people. Its numbers seem to be gradually increasing, possibly with climate change.

So this spring take time to stand and stare and watch these fascinating little insects going about their lives and wonder at how their lives interact with those of the flowers they pollinate and the solitary bees they parasitise, and then send in your sightings!

Sue Taylor
(Volunteer recorder for BBOWT, focusing on entomology)

 

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