New Book Excerpts #5: Small-headed Flies

I realise I’ve been banging on about this, but when you have a NEW BOOK out, you have to, so here’s Another soupçon from it. This time, the small-headed flies, the comical appearance of which belies a dark secret. Incidentally, I’ve got copies of the BOOK FOR SALE, signed by me and Carim Nahaboo. Message me for details. 

“As the old saying goes: “tired of small-headed flies, tired of life.” Outside of entomological circles these are not well-known animals, but they deserve to be even on looks alone. They’re not easy to find either. In many years of looking for insects I’ve only ever seen a couple of them, so their rarity adds somewhat to their cachet.

What with their comically tiny heads, which are little more than just eyes, hunched backs and dumpy bodies, they have air of innocence about them, but their cute appearance hides a dark secret. Like so many other insects – probably the commonest insect lifestyle – they’re parasitoids and as larvae they consume spiders from the inside out.

The female fly deposits a batch of eggs on or near a spider’s web, which hatch into a number of active larvae. These seek out the host and one of them will win the small-headed fly equivalent of the lottery and manage to get inside the unsuspecting spider, often through a leg joint. From there they wriggle to the arachnid’s book lung and sit tight, sometimes for years, waiting for the doomed host to grow to a sufficient size. When the time is right, the fly larva somehow manipulates the behaviour of the spider, making it spin a protective web before consuming it…”