Biter

posted in: Flies, Invertebrates, Worcestershire | 0

I took an early trip to Trench Wood this morning, knowing that I was scheduled to spend much of the day at my desk, and wanting to get some invertebrate therapy first. This, though, wasn’t quite the invertebrate I had in mind.

I was using the long lens, which has the advantage of allowing you to shoot your subjects from a sufficient distance not to put them to flight, but in contrasty and windy conditions it can sometimes ignore the thing you’re looking at, and focus instead on something behind it. In this case I was shooting a rather lovely lacewing when the stem it was clinging to blew sideways, and the camera latched firmly onto this horsefly, a few stems back. I was out of the glade and off up the ride in a flash, without bothering to check the sex – it’s only female horseflies that bite, because they need protein to help them make their eggs, while the males content themselves with pollen and nectar, but better safe than sorry.

In the event my decision may have been a wise one. This Tabanus bromius is a female, which is shown by the gap between her eyes, and more pertinently by her sharp, slicing mouthparts. The eyes of both sexes are brown, with green and red iridescence and a single transverse purple stripe, but the eyes of female horseflies always seem brighter and more obviously iridescent than those of male specimens. Both the iridescence and the stripe disappear soon after death.

According to Steven Falk, “T. bromius is the most frequent medium-sized horsefly of southern Britain but is rare north of the Midlands. It can found in a variety of habitats including meadows, heathland, open woodland and sometimes suburban locations. The predatory larvae have been found in soil under turf, in the damp moss of a tree stump, and in mud beside a stream. Adults fly from May to July and females will take interest in humans and also parked cars.” Hmmm.

I’ve only been bitten by a horsefly once in my life, nearly thirty five years ago, but I remember the occasion vividly and I’m not keen to repeat the experience. Next time I go to Trench Wood I think I’d better take some live bait with me. And if R gets wind of my plan, and declines to come along as decoy, I’ll just have to dress appropriately. I wonder where you can buy beekeepers’ outfits…?