Hairs distinguish tachinid flies

Sunday, September 9, 2012

I photographed this fly as it sat on my finger. It is a member of a species of flies called tachinid flies. There are countless numbers of tachinid flies throughout most of the world. In North America alone there are well more than 1,000 different variations of tachinid flies.

The one shown here is typical for Southeast Missouri. It is almost always seen outdoors. It is a bit larger and more colorful than its cousin, the house fly.

This particular kind of tachinid fly is relatively easy to distinguish from other flies by its hairiness and especially the spiky hairs at its rear end. These flies do not bite humans, but as this one has done, may alight on your finger and investigate for sweat or oils present on human skin.

Tachinid flies feed on nectar from flowers which makes them an important pollinator insect. They will also eat aphids.

Through the Woods is a weekly nature photo column by Aaron Horrell. Find this column at to order a reprint of the photo. Find more work by him at the Painted Wren Gallery.

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