Nature on our doorsteps: The great pretenders
At a quick glance, this hoverfly could be mistaken for a White-tailed Bumblebee

Nature on our doorsteps: The great pretenders

Some flies look very like bees and wasps. To tell them apart, we sometimes need to get a bit closer.

There are two key differences to look for.

The first is that bees have four wings, while flies only have two.

Instead of another second pair of wings, a fly has a very small structure on each side of its chest called a haltere.

These halteres balance the fly when it is flying, and they help it to change direction very rapidly.

They also help stabilise the fly’s head during these fast manoeuvres.

The second key difference is that flies mostly have short stubby antennae.

White-tailed Bumblebee

A bee’s antennae are much longer and are slightly bent into an ‘elbow’ shape.

Mimicking the look of a bee or a wasp is a useful trick for flies like hoverflies, as it can help them avoid predators.

Birds that normally avoid bees and wasps are also likely to avoid anything that even vaguely looks like these stinging insects.

Some mimic flies, however, can also sound like a buzzing bee.

At least, scientists tell us, they sound like a buzzing bee to us. Birds, however, are apparently much smarter than that.

It seems that birds can still tell the difference, and that they are not fooled by the mimic fly’s imitation buzz.

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