A Bee Mimic

Monday 9th October 2000, 1/2, West Yorkshire

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IN THIS MORNING'S E-MAIL there's a question from a 7th grade student;

'I'm doing a small science project on the Drone-fly,' the student explains, 'and my understanding is that they use mimicry. They look like a small bee, and so I was wondering what they use this for. What animals are they protected from by using mimicry?'

I'm usually wary of completing someone-else's project, but this question intrigues me. Here's the answer I sent;

pied wagtail

The usual suggestion, of course, is that for a harmless animal to mimic one that can protect itself (in this case with a sting) gives it some protection. The story is that a bird that has been stung by a Honey Bee will, to be on the safe side, avoid drone-flies. It sounds fair enough to me, but as this is a science project you shouldn't just accept it at face value. Scientists are incredibly sceptical.

I expect you've got to ask yourself;

Would you be fooled? - If the disguise is so poor that you and I can tell the difference between the two insects, would it really fool a sharp-eyed bird?
Is the honey bee on the wing before the drone-flies appear in the spring? (I guess it is) If the drone-fly emerges in spring before the honey bee the resemblance wouldn't be of much use. Birds would not yet have learnt to avoid the honey bee.
Is it such a good idea resemble another species? If the bee should become extinct the drone-fly's mimicry would be useless.
How long can you keep up a scam like that? The pretence of being able to sting can only work so long. Supposing every human who wanted protection carried a replica gun. Eventually the ruse would fail. Anyone thinking of attacking you would assume that the gun was probably a fake.

Before I get around to sending the message, while we are having breakfast, Barbara calls me to look at a 'strange-looking bee' that has just flown in at the back door and settled on the wall in a patch of sunlight. drone fly

It's a drone-fly, Eristalis tenax, and it really does look very like a bee!

Predators

I don't recall having seen a drone-fly being attacked by an insect but, no doubt, dragonflies would target them. If a drone-fly gets caught in a spider's web the mimicry would be of limited use because web-spinning spiders don't rely primarily on eyesight. I've seen spiders deal with bees, carefully dabbing them with their spinnerets until they have their prey bundled up in silk.

emperor dragonfly

The most spectacular bird I've seen going for bees was in Greece where a flock of Bee-eaters were circling above a hill village. We could hear the 'snap' of their beaks as they caught bees (or wasps perhaps). Bee-eaters are blue and yellow, reddish brown, green, black and white. They're probably the most colourful birds that you can see in Europe.

Richard Bell,
wildlife illustrator
E-mail; 'richard@willowisland.co.uk'

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