Monday, 31 December 2012

House Spiders

It was the late Gordon Osborn, a genial retired butcher from Olney, who first - inadvertently - guided me towards the study of spiders. His own interests were snails and fleas, and we noted that certain invertebrate groups were very neglected. I felt that spiders were much maligned and therefore given little attention, not realising that in the Northamptonshire village of Wadenhoe lived Eric Duffey, one of Europe's most distinguished arachnologists. He had, in 1956, discovered one of Britain's largest and rarest spiders, Dolomedes plantarius, at Redgrave Fen; but for Eric's efforts the spider would probably have become extinct there. When Eric retired to France I took over as Spider Recorder for Northants. However, I digress...

I do limited work on spiders nowadays but generally check out any which, for one reason or another, come to my attention. In our house in Byfield I have noted about a dozen species, of which four are "regulars". I mused on these matters when contemplating the imminent removal of the Christmas decorations for there, tucked away in the corner of our living room, was a large, untidy web of the Daddy Long-legs Spider Pholcus phalangioides. This species is rarely, if ever, found outside buildings in Britain, suggesting that it is not a native to this country but is a relatively recent arrival. People who dislike spiders may be pleased to learn that other spiders form a large part of the diet of Pholcus so arachnophobes have a dilemma: leave it to keep down the population of spiders in the house, or get rid of it. It does not need to be described in detail for no other house spider has this combination of long legs and a large tangled web. Incidentally phalangioides means "like a harvestman (Daddy Long-legs)".

The Mouse Spider Scotophaeus blackwalli is also more or less confined to houses, and turns up here from time to time. I'm afraid it is quickly dispatched as it has been known to ruin insect collections by chewing the specimens; I'm not going to expose my collection to this danger. It also has a rather nasty bite which can take a week or more to clear up. This species is 8-10 mm long with the females being generally larger than the males; it has a mouse-grey colour, giving this spider its common name, and is more or less nocturnal in habit.

From time to time, often on a late summer evening, a large, long-legged spider will emerge from behind an item of furniture and dash across the floor. This is the House Spider Eratigena atrica (=Tegenaria gigantea). Though most often found in buildings it does occur in hollow tree trunks, beneath overhanging banks, and so on. The females reach a body length of about 16 mm, justifying the specific epithet of 'gigantea' - and they will bite, although only under unusual circumstances. I once had a large female in a specimen tube and had mislaid the stopper, so I put my thumb over the tube while I rummaged around. Big mistake! However, the well-deserved bite was no worse than a wasp sting and the pain lasted less than 48 hours. The males are smaller than the females and it is males which are most often seen as they go out, reeking of Old Spice and carrying flowers (Now Tony, don't be silly!) in search of females.

The fourth, and most common spider in our house is Amaurobius similis, but you will be relieved to know that I'm leaving comments on this species until a later blog.



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