Thursday, July 29, 2010


In my last post I mentioned the day that John O’Sullivan and I had spent around Studham surveying for hoverflies. Today, John e-mailed me to say that a small dark hoverfly that I had netted from the top of a Hogweed umbel had been identified as Cheilosia scutellata, a first for Bedfordshire.

The other notable record was the presence of 5 of these: the impressive Volucella inanis, which has been expanding its range northwards over the last decade or so. It looks like a giant wasp and is, indeed, a wasp mimic, its eggs known to be laid in the nests of the Hornet and of some of our common social wasps. One reputable source notes that the strangely flattened larvae can ‘fit into the larval cells beside the wasp larvae on which they feed’ [Ball & Morris, 2001], whereas another hoverfly aficionado writes, ‘the larvae probably feed on organic debris accumulating in the nest cavity below the nest itself’ [Falk, 1991]. What’s amazing to me is the fact that they’re there in the first place!

Another insect that’s been expanding its range quite dramatically in recent years is this one: Roesel’s Bush-Cricket. It used to be a rare inhabitant of coastal meadows. Why Roesel’s? Because it’s named after the German entomologist, August Johann Rosel von Rosenhof, who studied insects and painted them. He died in his mid-fifties, and I can’t help wondering whether he would still have been able to hear this species calling towards the end of his life as the high-pitched song, created by rubbing the wings together, is not easy to pick up as our hearing deteriorates with age. I can still hear them…but for how much longer, I wonder?

Notice how long the wings are on this individual, extending past the end of the abdomen. This makes it the ‘macropterous’ form. In the usual form the wings only reach about half-way along the abdomen. I’ve never noticed this before. The author of the Wikipedia article on this insect states, ‘This form appears predominantly during hot summers and enables the species to extend its geographical range rapidly while conditions are suitable; such migrations may also be in response to local over-population.’

This individual was close by – I think it’s a Common Green Grasshopper, though I’m happy to be corrected.

Here’s a question for you to think about: What colour is Grasshopper blood? I was surprised when I found out. Any ideas?

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