Letting go is suicide

As I was sorting through some pictures for a lecture I’m giving (brownfield ecology, no lice there), I came across several close-ups of head lice I’d taken when we had an infestation some years ago. The nymphs were really too tiny, even for a macro lens, so I’d kept an adult alive in a small glass tube. A twist of damp tissue prevented it drying out, and I kept it in my trouser pocket to keep it safe and warm.

Plonking it down onto a piece of art paper made the right background in terms of colour balance, but the louse was lost against the flatness and struggled to move. It did not look right. Then I remembered the clippings from the kids’ haircuts a few days earlier. We’d thrown them out into the garden. I don’t know, something to do with improving the tilth of the soil maybe. Anyway, the cuttings were still there and I rescued some sprigs, scattered them on the paper and released the louse.

The louse was very nimble on its claws.

It was remarkably active, considering it had not eaten for several hours; but I put this down to the fact that I had been keeping it in safe and humane conditions. It shot off across the strands at top speed. From memory, I’m guessing it moved at about 2 cm/sec. This was enough to make it quite interesting trying to get the thing in focus as I chased it back and forth across the jumbled strands. It also reminded me why head lice are so difficult to spot on a cursory examination of the dry scalp, and how easily they can scramble over from one victim to another.

What I had in my favour, though, was the fact that the head louse never once let go of the hairs. It ran backwards and forwards, up and down, left and right, exploring every inch of its manufactured backdrop, but it had nowhere else to go; it was trapped. Because, of course, for a louse, letting go is suicide.

Head lice are tiny compared to humans, they are perhaps one hundred millionth the size of their host. If they let go for an instant, they will get injured, or they will get lost. Either way, they will be dead. Head lice do not wander off across the pillow looking for another head to invade, nor do they sit on chair backs, or shoulders, hoping for another hairy human to stroll past so that they can scramble aboard. Within minutes they will start to cool down, and dehydrate. Their body movements will slow, their internal metabolism will start to fail and all the complex physiological workings of their bodies will start to corrupt. After a couple of hours away from its warm moist scalp home, the louse is beyond recovery; its legs may still twitch, but they are its last desperate gropings. No, if a louse lets go, it is as good as dead.

Not available in all toy shops

All those Star Wars Lego sets came in real handy after all

We are a Lego-enthusiast household and the brick box, already full to bursting, has just received a new injection of Christmas model sets. After the success of the spawn-of-the-Devil-maggot-child baby Jesus, three wise arms dealers and Bethlehem’s famous zombie carol singers, a Lego head louse seemed the obvious choice for a father/6-year-old bonding session.

And I have to say, I’m thrilled with the results. There is a certain pleasing anatomical correctness in its proportions, although perhaps the antennae could do with being a fraction longer. I particularly like the contrasting sclerotization of the thoracic and abdominal segments, and the translucent body showing the meandering blood-filled intestinal tract.

Oh, and it’s a female, you can tell by the prehensile nit-glue-manipulating gonopods at her tail end.

Next up…? A cat flea? Or a bed-bug maybe.

A new skill-set for the advanced nit-picker

Exactly how common are head lice?

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.