Horsefly Sexism

Sexism in science is getting a lot of entirely justified public criticism at the moment. But I hope the critique doesn’t eventually go so wide and so deep that it starts to apply to non-human species. For example, it is usually the female biting flies that go in for blood-sucking. So if a horsefly lands on my jacket sleeve and I can see clear space between the eyes, I flick it off immediately. If I can see that its eyes meet at the top of the head, it’s a male: safe!

A male, probably one of  the Tabanus sp. He's safe to approach!
A male, probably one of the Tabanus sp. He’s safe to approach!

Call it horsefly sexism if you like. I call it prudence! Horseflies really are beautiful animals – take a look at their oil-slick eyes – but unless I’m absolutely sure my new shiny eyed friend is a he then I don’t usually spend long admiring them. Horsefly bites can be excruciatingly painful. Having said all that they can be quite sluggish when resting in an exposed sunlit spot like the top of a fence or gate, so you might get away with admiring even a female for a while.

As much as I dislike being bitten, I try as far as possible to ask a few questions before reaching to squash an insect nowadays. Indeed apart from reflexively slapping mosquitos as they settle on the back of my hand I rarely kill something just because it is annoying me. I deliberately kill plenty of insects for identification, certainly outweighing the modest numbers I ever used to kill out of ignorance or irritation, but conversely the more I kill the more I also respect them as living animals. So I may be a horsefly sexist, but I’m prepared to stand up and be counted as a campaigner for horsefly equality.

Whilst preparing this I stumbled on some beautiful pictures of horseflies and fascinating facts on the blog of Devon based blogger and artist Tim Worfolk. Also see the Flickr pages of entomologist Steven Falk for images of many of the British species, including the inch-long Tabanus sudeticus!