...suddenly something caught my eye - a dark flitting creature an inch long, with bright red legs and a menacing pointed tail.
The fabulous fine weather of Sunday saw me in the garden trimming back a rose bush that was reaching threateningly across the path at head height. Suddenly something other than a branch of thorns caught my eye - a dark flitting creature an inch long, with bright red legs and a menacing pointed tail. It could only be one thing: the spectacularly intimidating, yet bizarrely and intriguingly named Pimpla hypochondriaca.
If there were any insect that deserved to have an extraordinary English name given to it, then this is the creature. But, sadly, it is just 'one of the ichneumons', which is quite frankly pathetic. Ichneumons are large and striking insects, allied to bees, wasps and ants. (Ichneumon is also another name for the Egyptian mongoose but we don't get those in East Dulwich). All ichneumons are parasitic, laying their eggs in a wide range of insects, but especially moth and butterfly caterpillars. The venom injected at the same time contains an immunosuppressant, preventing the immune system of the host insect from fighting back. The eggs hatch and the ichneumon grubs then eat the insect alive, from the inside. Although they are amongst the most important of biological control agents, they are incredibly poorly studied; the few identification guides are highly technical and the nomenclature is constantly being revised. Despite their large size, bright colours and fascinating life histories, most entomologists ignore them.
This is one of our largest and most easily identified. There is nothing else quite like it. And it's very common, occurring throughout the country in parks, gardens, meadows, woods and forests. It parasitizes a huge range of moth caterpillars, including common garden species like yellow underwing, Noctua pronuba, and lime hawkmoth, Mimas tiliae. It is not even put off by the stiff hairs and silk web nests of browntails, Euproctis chrysorrhoea, which is where I photographed this one a few years ago. The one on the roses was much too quick and had vanished before I could even remember where I'd put the camera.
I'm still left guessing how it got its peculiar scientific name. In medicine, hypochondria is apparently derived from the Greek, hypo meaning 'below' and chondros, the cartilage of the breast bone. According to the ancients, this part of the abdomen, containing such mysterious organs as the liver, spleen and gall bladder, was the home of melancholy and other emotions concerned with worry, fear and phobia. Quite what Anders Jahan Retzius, the Swedish chemist, botanist and entomologist who first named the insect in 1783, was thinking, perhaps we'll never know.
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