Beeflies - Bombyliidae

To identify flies to family level use a simple wing venation key such as A Key to the Families of British Diptera, an AIDGAP by D. Unwin, published by the FSC and available as a free download (scroll down to the titles list) or a more detailed key which includes many physical characters such as The European Families of the Diptera by P. Oosterbroek. The expert dipterists on the DipteraInfo forum are also very happy to identify, often to species level, from good photographs.
 
The typical beefly is brown and furry with spindly legs and an unwieldy looking proboscis ('tongue') that does not retract. They frequent sunny spots with plenty of flowers, hovering in front of nectar sources and neatly inserting their long proboscis. They are generally quite large flies, sometimes with an audible buzz, so people notice them regularly. Many entomologists have a soft spot for them because they are a fly that can be presented to the general public in an entirely positive manner - they have the requisite cute and cuddly look and they are fun to watch. They don't sting or bite, or spread disease and are good pollinators.

The most common and well known beefly is the early spring species the Dark Edged Beefly Bombylius major, but there are other common species that do not have the long proboscis and are darkly and dramatically patterned, especially on the wings. Most species are parasites of solitary bees and can often be observed cruising slowly over sunny patches of bare earth, searching for bee nest holes. They will pick up sand on the tip of the abdomen and then flick it and their eggs into the bee nests whilst hovering over a suitable site.

If you have seen a beefly and would like it identified you can post photos on the Diptera.info forum, where there are a couple of beefly experts who respond to questions regularly. Your photos need to be in focus and give close detail, as many beeflies are difficult to identify. The photo below, for instance, is not good enough to even be sure of the genus, much less give a species name.

A typical beefly, photographed in Preuilly-sur-Claise, May.

Photographed by Loire Valley Nature:

All photos will enlarge in a new window if you click on them. Row 1 Left & centre Bombylius venosus. Right Villa hottentotta.








A Villa sp is joined by the hover fly Sphaerophoria scripta on a Wild Carrot Carota daucus umbel.

A Villa sp is joined by the hover fly Sphaerophoria scripta on a Wild Carrot Carota daucus umbel.

A Villa sp on a Wild Carrot Carota daucus umbel.

A Villa sp is joined by the hover fly Sphaerophoria scripta on a Wild Carrot Carota daucus umbel.

A Villa sp is joined by the hover fly Sphaerophoria scripta on a Wild Carrot Carota daucus umbel.

A Villa sp is joined by the hover fly Sphaerophoria scripta on a Wild Carrot Carota daucus umbel.

A Villa sp is joined by the hover fly Sphaerophoria scripta on a Wild Carrot Carota daucus umbel.
Unidentified Bee Fly.
Unidentified Bee Fly.
Unidentified Bee Fly.
Close up detail to show the wing venation of Villa sp. Wing venation patterns are always key to identifying flies to family level. All Bee Flies have wing venation similar to this. Notice that the veins reach the trailing edge of the wing.

For comparison, this is a close up detail of a Volucella sp Hover Fly Syrphidae. You can easily see the differences in wing venation for a fly that belongs to a different family. Note that the main veins do not reach the trailing edge of the wing, but finish at a cross vein at a right angle (more or less) which runs parallel to the wing edge.

More information:


Species account for Anthrax anthrax.
Species account for Dark Edged Beefly Bombylius major.

4 comments:

  1. Susan, I am a bit confused by the Villa sp.
    It looks more like a hoverfly than a beefly...
    does it behave the same way?
    is it also parasitic on bees?

    ReplyDelete
  2. Tim: The wing venation is quite different. Hover flies all have 2 main veins that stop short of the trailing edge of the wing and meet a cross vein that runs parallel with the edge. With bee flies all veins run to the edge or peeter out just before, no outer cross veins. Jizz is different, but they do behave similarly when nectaring. Bee flies tend to have broad dorsally flattened hairy bodies. Similar looking hover flies are more rounded in body shape. We only know random snippets about Villa spp lifecycles. They seem to parasitise lepidoptera, especially noctuids, but there is a confirmed record of a bee host (Osmia) in the south of France.

    ReplyDelete
  3. Yes, I can see the hairiness in the Villa sp. pix... but to me the body looks very much the same as a hoverfly... albeit a very hairy one.

    The "ordinary" Bombylius sp. ones also seem to have much smaller wings in relation to their bodies...
    But I can see the difference....
    especially when compared to the enlarged wing on the Volucella zonaria entry.

    Given your skills and training, how about a page showing wings from different species?
    With links to relevant section??
    Sort of like a visual key for us 'thicko's???

    ReplyDelete
  4. Tim: I've added a preamble to all the fly entries giving a link to Unwin's AIDGAP Key to the families of British Diptera. It mainly uses wing venation, with lots of illustrations. It is simple and easy to use. No point in me reinventing the wheel.

    ReplyDelete