The Enemy Within – Conopid flies as parasitoids of bees and wasps in Britain

Have you ever been out for an early-morning walk in the summer and noticed bumblebees, bedraggled and soaked with dew, languidly stirring on the stems of thistles? Did it occur to you that this was odd - surely bumblebees have nests to go to at night? Perhaps, like I once did, you thought that these bees had been caught out by sudden change in temperature or the weather, and had pitched up for the night outside the nest.