Scaly Bee Fly

2009 August 29

S_ caught this one in the yard on August 10, and put it into one of the little bug-capture cages that Sam got from her grandparents (they bought them at the local dollar store for practically nothing)>


It looks like a bee at first, but on closer examination we can see that it only has two wings, not four, making it some kind of bee-mimicking fly.


There are a bunch of species of robber fly that are bee mimics, and I thought at first that it was one of them. Particularly when it got out of the capture cage, and shot to the window so fast that I didn’t even see it traveling (it was almost like it teleported from the cage to the window about 10 feet away). But, looking closer, it wasn’t quite right for a robber fly. Particularly the strongly humped back, the feathery antennae (very long and complicated for a fly), and the kind of black tuft on the tip of its abdomen.


Poking around a bit more, I realized that it was almost certainly one of the Scaly Bee Flies, genus Lepidophora. Not only do these have the right body shape and the odd antennae, their hairs also have that same odd, scale-like structure that makes them look kind of matted.


There are evidently only three species of Lepidophora in North America. The ones furthest north are usually(but not always) Lepidophora lutea, which are distinguished by the “yellow hairs on the fourth abdominal segment”. I think this one has yellow hairs on the fourth abdominal segment, so let’s go with that one.

These are actually in the same family (Bombyliidae) as the bee fly from last week, and have a generally similar proboscis that they use for drinking nectar:



There seems to be some argument about what they are mimics of: they could just be straight-up bumblebee mimics, or they might be mimicking the robber flies that mimic bumblebees. The idea that they are actually robber-fly mimics is supported by the way they act: they perch dead-still on things, and then abruptly dash off, the way robber flies do. This is unlike bumblebees, who tend to hover a lot and kind of, well, bumble about. I suppose that robber flies are a bit dangerous in their own right (I’m told they can give a nasty bite), and so being mistaken for either a robber fly or a bumblebee would be somewhat likely to make a predator look elsewhere. So, it gets kind of a twofer in the mimic department.

Of course, this fly isn’t dangerous itself. It just flies around flowers and drinks nectar, while looking for an appropriate host for its eggs. Unlike last week’s bee fly, this one isn’t looking for a solitary bee for its host – it’s looking for a solitary wasp. It’s the same principle otherwise, though: it looks for a wasp that is gathering materials to stock its nest, and then shadows it back to its burrow. Then when it gets a chance, it nips in and lays an egg when the wasp isn’t looking, and then suddenly the wasp is stocking a nest for the bee fly larva instead of for her own larva. Which just goes to show, life is hard.

2 Responses
  1. August 31, 2009

    What afantatsic looking creature

  2. September 2, 2009

    Off topic, just wanted to show you the link:

    Awesome stuff.

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