The day started bright and sunny, and the garden provided me with some nice inverts, including the first Narcissus Bulb Flies (Merodon equestris) and the first Batman Hoverflies (Myathropa florea) of the season. Both these species are unusual among hoverflies in being loud and assertive, and even irritable if you get in their way, which on the face of things is odd behaviour for creatures that don’t have a single weapon to their names – but they’ve evolved to mimic more dangerous insects, and their behaviour tends to support those impersonations. The Narcissus Fly comes in a range of different colours, which at a casual glance look reasonably like bumblebees of various types, and while the Batman Fly looks only very vaguely like a wasp, its auditory impersonation is much more convincing; because of its habit of buzzing furiously just out of sight by my ear or behind my head, my personal name for it is the B*stard Fly.
By the time I made it to Cleeve Prior Mill in search of dragons the weather had turned dark and threatening, so it wasn’t much of a surprise that there was no sign of the Scarce Chasers I’d been hoping for. In fact, apart from about a million flies – some of them biters – there wasn’t much around at all, which made me suspect that the forecast rain couldn’t be far away. So on my final pass around the clearing I was surprised as well as pleased to find another Batesian mimic, in the form of this very striking Wasp Beetle.
Adult Wasp Beetles have a short season on the wing, from May to July or thereabouts, and live mainly on pollen and nectar, though females are reputed to eat the odd small invertebrate to provide them with extra protein in advance of laying their eggs. They do this in deciduous deadwood, where the larvae develop just below the bark, helping to break down the wood and return its nutrients to the soil. When they’re ready to pupate they burrow deeper into the wood, from where they emerge the following spring to complete their own life cycles. It’s said that the adult beetles back up their visual impersonation of wasps by behaving in an irritable and erratic fashion, but I’ve never seen that myself, and through the entire time I watched it this individual was entirely still and passive.
R: L2, C9, D2.
