Thunder thighs #2

Thick-legged Hoverfly (Syritta pipiens)

We've been struck this summer by the relatively low number of insects in the garden compared to years past. Hoverflies in particular are notable by their absence, with only a fraction of the hordes we saw last summer. Despite that, I'm still racking up new species. The Thick-legged Hoverfly (Syritta pipiens) is one that Mike spotted last year but I managed to miss. This slim little nectar feeder is one of the smaller hoverfly species, measuring only 4 to 7 mm (about 1/8 to 1/4 of an inch) in length. Those bulging hind femora – its "thighs" – are distinctive. The combination of its hefty femora and the dusty grey sides to its thorax (the part of the fly right behind its head) are diagnostic; no other British hoverfly shares those two characteristics. It's a common and widespread hoverfly, found right across the UK, though missing from the highest and most exposed locations. Larvae develop in damp, rotting compost, silage and manure. Adults fly primarily in the late summer and into the autumn, with numbers sometimes augmented by arrivals from the continent. They feed on many different flowers, and can be abundant on Common Ivy (Hedera helix). We'll have to keep an eye on our small ivy patch this autumn to see if they're still around then. Britain's Hoverflies says the males can be quite territorial, facing off and shoving each other back and forth until one finally gives up. That could be amusing to watch!