Ask an entomologist how common purple emperors are, and they’ll tell you “very scarce”. I agree. I’ve never seen one myself. But I know where they occur, in large open woodlands in Wiltshire, Hampshire and the western Weald. I found that out by looking in one of my many butterfly books.
Ask about 7-spot ladybirds and you’ll get a different answer; they’re common across most of Britain. I get them in my garden. Violet ground beetles? Still pretty widespread, but perhaps not so common as once were. Hornets? Hmm, some research might be needed here, but it would not take long to come up with details of their UK distribution, their burgeoning numbers, and increased geographic spread particularly in south-east England.
So how common are head lice? I suspect that most entomologists would be hard-pressed to come up with an accurate answer. There is no head louse recording scheme, louse-spotters society or fancy Phthiraptera breeding club. Most entomologists would be left scratching their heads in puzzlement. If they resort to the on-line distribution map provided by the National Biodiversity Network (NBN) they will find this:
Not sure what’s so special about Llanbedr and Battle, but it seems they are the lousiest places in Britain. In fact they are the only lousy places in Britain. That can’t be right.
I suspect that most entomologists have never seen a head louse. Perhaps this is because most entomologists are men. They are still. It’s a hang-over from the days of the leisured Victorian gentleman amateur. Men suffer head lice far less than women and children. Part of this is because head lice like the fine close hairs on women’s and children’s heads, rather than the rather coarser and often thinning hairs on men’s heads. Mostly, though, it is because women and children are more demonstrably affectionate — hugging, cuddling and touching heads together often. So maybe entomologists do not see head lice because they do not cuddle their children, they only shake hands with them.
I’ve had head lice. And to make a point, I showed some other entomologists at a scientific meeting up in London. The British Journal of Entomology and Natural History (volume 14, 2001, page 239) reports:
“Mr R.A. JONES showed … a live head-louse, … that he had plucked from his own scalp.”
As far as I know this is the only time such a lousy exhibit has ever been presented in these august circles. For some reason my record has not been picked up by the NBN recorders. Perhaps it’s because I did not give a 6-figure Ordnance Survey grid reference for my head.