From ghoulies and ghosties
And long leggety beasties
And things that go bump in the night,
Good Lord preserve us
Traditonal West Country litany.
The ancient litany quoted is perhaps a relic of the fears and superstitions which abounded in Britain and everywhere else when ignorance of our surroundings was much more evident than it is nowadays. What with education, books, insecticides, wildlife documentaries and so on there are not many fears of the unknown or mysterious left for us to worry about in our homes. But some remain of the most unexpected kind.
Our telephone at home stands in the hall on an antique walnut table. Being antique, the table is riddled with woodworm and full of their exit holes. For years my wife has complained that often after having been on the phone she has received mysterious bites or stings from some insect or other. My children have suffered similar experiences and have come out in terrible red, swollen eruptions at various times. We have naturally put these bites down to the notorious zanzara tigre (tiger mosquito), since the symptoms more or less correspond, even though we, by good fortune, have rarely found this insect in the house.
About three months ago I was on the telephone and, while talking, noticed two small (about 3 mm long) insects on my forearm. They seemed to be, at a glance, ants, but somehow, as ants, were not very convincing. Whatever they were they gave me two splendid stings which developed into large swellings which itched like mad. And the swellings lasted for a full ten days. So what were they if not ants?
The next time I found one it was crawling around on the keyboard of our computer. I put it under the magnifying glass and sketched it. It was superficially ant-like but more like a very thin, black, wingless wasp. My books didnt help. No sign of it in any of them until I discovered an Italian book, Animali Pericolosi by Maurizio Bigazzi and Giuseppe Gardenghi (Edagricole). At last the mystery was solved.
Scleroderma domesticum is a relative of the hunting wasp. The wingless females inhabit the galleries of various furniture beetles (woodworm). They seek out the larvae of the beetles, paralyse them with their very potent stings and lay an egg on the by now helpless grub. The egg hatches and the wasp larva finds itself with a live but helpless store of food. Scleroderma females produce eggs after mating with the rarely found, winged males which can even be their own offspring, or by parthenogenesis. That is, they do not have to be fertilized by a male in order to lay fertile eggs. The harmless males emerge and fly to find a female in another set of galleries to ensure that new genes are spread around to keep the population healthy.
Scleroderma has been called friend of antiquaries since it preys upon furniture beetles, but I strongly suspect that any antiquarian stung by the insect would not consider it to be a friend. And of course wood beetles are not only found in old furniture. They infest beams, stacked firewood, fallen trees, woollen mattresses and pillows. Scleroderma does not seek out human victims but will sting at any time, night or day, if disturbed. So you could be in bed or sitting on your antique sofa doing no harm to anyone and find yourself suffering for it.
To avoid unpleasant encounters and Roman flats are ideal sites for this insect you should ensure that there are no active wood beetles in the house (no beetles, no scleroderma). If they are active they usually leave traces in the form of little piles of sawdust under the furniture. There are plenty of proprietary treatments available or you could contact a firm offering professional help. Mattresses and pillows present more difficult problems but steam treatment should do the trick.
Please remember that Scleroderma domesticum is very small and easily overlooked. If noticed it is easy to dismiss it as a harmless ant, but its sting is very painful and leaves a weeping swelling which itches and lasts for at least a week. Treatment of the swelling with antihistamine cream helps, but not much. The British Natural History Museum adds that no long-lasting deleterious effects have been recorded. If any readers, especially those working or living with antique furniture, recognise these symptoms they should be on the watch for the presence of our little Roman friends.