I became an unwilling expert on pubic lice a couple years ago when I bought “crabs” online at the request of a reporter. Really. It’s a long story, and you can listen to a version of it here; the abridged version is someone calling himself “Lice Lice Baby” claimed he would sell you “Giant Japanese Pubic Lice” as pets. He re-branded his crab lice as “Seamonkeys in your Pants.”
The French call pubic lice “papillon d’amour”, but for all the happy euphemistic talk about “the ultimate sharing of your love,” crab lice are blood-sucking parasites. At the time, my primary concern was pointing out that deliberately infesting yourself with pubic lice was probably not a very good idea, and a public health risk.
This somehow made me the go-to person online for pubic lice, which is not, frankly, an expertise I particularly aspired to. I was talking to someone recently about public lice (now a regular occurrence) and I realized that I didn’t know the specific mechanism by which pubic lice suck (aside from the fairly obvious suckage of being infested). I did a little research, and what I found out actually made pubic lice creepier. I did not think that was possible.
One of my primary resources was a paper with this wonderful title:
BURNS D.A. & SIMS T.A. (1988). A closer look at Pthirus pubis, British Journal of Dermatology, 118 (4) 497-503. DOI: 10.1111/j.1365-2133.1988.tb02458.x
A closer look, indeed! This is a scanning electron micrograph of the sucking end of a crab louse, magnified about 1000 times.
Pthirus pubis is a member of the Order Anoplura or ‘sucking lice’. It is a solenophage (vessel feeder—from the Greek ‘pipe’ + ‘eating’), introducing its mouthparts directly into a blood vessel to withdraw blood. The components of the mouthparts responsible for probing the skin and piercing a blood vessel are kept withdrawn within the head unless the insect is feeding… In the front of the head is a small, snout-like tube, the haustellum, which is soft, eversible, and armed with teeth. Figure 5 shows the haustellum retracted, and the buccal teeth are clearly visible.
But wait! There’s more!
When the louse is about to feed… the buccal teeth rotate outwards. The teeth cut into the epidermis [skin] with a movement compared to that of a rotary saw, and the haustellum is gradually driven into the dermis. It eventually comes to rest with the buccal teeth fully everted, anchoring the mouthparts in the skin….The stylets are advanced into the dermis as a single bundle and probe for a small blood vessel. Once the stylet bundle has pierced a blood vessel feeding begins. [emphasis mine]
If you haven’t already unconsciously crossed your legs while reading this, this next bit should do the trick. One of the characteristic signs of pubic lice feeding is little blue spots on the skin. It’s a combination of blood leaking out after that mouth-needle is withdrawn and a reaction to the saliva of the louse. Another symptom of a crab louse infestation is described as “black powder in your underwear.” That powder is your dried up blood, after the louse has digested it and pooped it out.
I’m not sure that anyone besides me really needed to know this information, but it is a fascinating example of how insect mouth parts have evolved to make them highly successful external parasites!
You may have heard that I told a story at the ScienceOnline2012 conference. If you missed it, here you go!
Everything I said is true; there are even photos. (Think carefully before you click this link. You’ve been warned.)
Ben Lillie’s story is right after mine, and is very different, and incredibly powerful. I got a little verklempt. Ben now runs The StoryCollider, which is an amazing project to collect science stories.
I had been mentally drafting something about storytelling and science, but then Emily at This View of Life wrote something so spot on in summary of ScienceOnline I defer to her:
“I think that this tendency to focus on the sexy or the gross, the morbid or the taboo, is not just a symptom of our four days of very little sleep, more than a little alcohol in some cases and a deep sense of intellectual and cultural overstimulation.
No, this is an integral part of who we are as a group. We focus on duck penises because we almost have to.
We are all story tellers, whether scientists, journalists or educators. We take data and create hypotheses. We take facts and construct narratives. We take a curriculum and transform it into inspiration.
What she said. Go read the rest.
I’ll try to put together a more meaningful summary of the Science Online conference later this week, but for the moment I’m enjoying the accomplishment of briefly trending on Twitter. Even if it is for telling a story about Seamonkeys in your Pants.
A fabulous new development in louse control! I’ve written before about the problem of head lice becoming resistant to commonly used pesticides, making treatment much more difficult. A new device received approval from the FDA to be this year–and it’s a lot of hot air.
Goates, B., Atkin, J., Wilding, K., Birch, K., Cottam, M., Bush, S., & Clayton, D. (2006). An Effective Nonchemical Treatment for Head Lice: A Lot of Hot Air. PEDIATRICS, 118 (5), 1962-1970 DOI: 10.1542/peds.2005-1847
This device is a great story of how basic ecological research can lead to improvements in human health. It all starts with birds.
Those of us who keep chickens or work with wild birds know that they have an amazing assortment of ectoparasites–parasites that live on the outside of the body (“ecto” = external). Most of these are called “feather lice.”
Feather lice are a fascinating group of animals; the researchers in this lab have studied, among other things, how lice have evolved to match the color of their host birds. I think it’s safe to say that Dr. Dale Clayton, the lead researcher in this story, is Mr. Bird Lice. Over the last 2 decades, he’s published a steady stream of fascinating papers (and books!) about lice and their co-evolutionary relationships with their hosts.
It was because of Clayton’s research that the University of Utah lured him away from his job at Oxford in the late 1990s. Unfortunately, Clayton discovered exchanging jolly old (damp) England for Utah’s arid climate made keeping his lousy subjects alive extremely difficult. In fact, his lice colonies dried out and died.
Having dead research subjects will put a serious dent in one’s research productivity.
His travails in lice-rearing, however, were what set a lightbulb off when his children came home with head lice. If his research lice dessicated and died, could he make head lice dry out and die too? Alas, it proved to be a much harder puzzle than he thought:
“Over the next several years a variety of methods were tested in Clayton’s lab, ranging from the use of chemical desiccants, to heat caps fitted with electrodes, to rice bag caps heated in a microwave, to various hair dryers and blowers up to the size of a leaf blower “
After almost 20 years of tinkering, the Lousebuster is now FDA approved and on the market. It also happens does a really, really good job of killing the insects using only hot air!
I know what you are thinking–unfortunately, it is not enough to have a blow-dryer, as you can see here in the results comparing the percent of lice being killed with different methods. (I also am rather relieved that wall-mounted hand driers were not effective. I can only imagine the lines at the airport bathroom if families traveling decided to do a little de–lousing between connections.)
The other nice item is that the company selling the Lousebuster requires that anyone purchasing them be certified in their use. That means that no one should have a scalded scalp, and it should actually perform at the 95-99% louse mortality levels reported in various publications.
A newer version released December 2010 is quieter and “works on curly hair”.
So hoist one to toast Dr. Clayton and his lab in their demonstration of how basic research pays off for all of us!!
I surf around on WordPress every now and then and see what other people are writing about insects. Good news: Are you troubled by dreams of ectoparasites? Now there is a solution!
The symbolic meaning of Lice (at Symbolic-Meanings.com).
But I digress.
Generally, the more florid my dreams, the more likely that I’ve eaten something regrettable just before bedtime. (Burritos before bed–not a good idea.) Dreaming of lice perhaps means that you are concerned for your health, or that you saw something on the news that made you fear them. Head lice are a pretty common occurrence in kids, and it’s a major problem I’ve covered before. But — a spinal condition? Overwork? From her post:
“When Lice come to our attention in our dreams, it can be an indication that our subconscious is trying to tell us to let go of some pesky people or ideals in our lives. When we are being “sucked dry” by too many responsibilities, too many obligations, or torn in too many directions by well-meaning people, the Louse will come to our attention as a message to withdraw ourselves and resist being pulled into situations we do not wish for ourselves.
The fact that you were dreaming of Lice around your head and down the spine indicates that you may be dealing with some challenging thoughts (the head & spinal cord being symbolic of the nervous system & the origin of thought), that there are many choices before you – and all of them may be “bugging” you.”
This seems a little over elaborate. How about just “you’re freaked out your kid will get lice. They are creepy”?
From farther down in her lice post:
Furthermore, the Louse never takes more from its host than either can handle (for to do so would destroy its own livelihood). This is a message that we can all learn from. Sometimes when Lice are in our dreams it indicates that we are either asking too much from our loved ones, or they are asking too much of us.
That is not true. Exanguination by lice does happen, although it’s usually limited to small animals. This idea that nature is in balance and as it should be is overly romantic, and a common mistake in New Age-y types.
My grandparents had Edgar Cayce’ dream books when I was a kid, and I spent some time thinking about his system of symbolism. Carl Jung also mentioned insects occasionally; but mostly in a way to relate to synchronicity. Which… is completely unsupported by evidence. Like this dream interpretation stuff. Eventually, I rejected it all.
There is a fairly large body of work about dream interpretation that has a more scientific background. Some of the coolest insights comes from neurological work on dreaming deficits in brain-damaged patients; it’s helped locate a lot of the actual brain structures involved in dreaming.
Generally, bizarre dreams are hugely over reported; most dreams are simply the same as everyday experiences. From a scientific review paper:
“Taken together, these detailed descriptive studies provide a consistent picture of REM dream reports as portraying a reasonable simulation of the dreamer’s waking world. The dream scenario is original, but not usually fantastic, and the emotions are generally appropriate to the situation when they are present….
Despite the originality and creativity that is displayed in the cognitive production of dreams, and even given the aspects of dream content that are not understood, most dreams are more realistic and based in everyday life than is suggested by any traditional dream theory. In addition, much dream content seems more transparent than might be expected by clinical theories that emphasize disguise and/or symbolism in understanding dreams.” [emphasis mine]
Feel free to offer up your more interesting insect dreams in the comments!
Domhoff, G. W. (2005). The content of dreams: Methodologic and theoretical implications. In M. H. Kryger, T. Roth, & W. C. Dement (Eds.), Principles and Practies of Sleep Medicine (4th Ed., pp. 522-534). Philadelphia: W. B. Saunders.
S. Schwartza, T. T. Dang-Vuc, A. Ponza, S. Duhouxa, P. Maquetc. (2005). Dreaming: a neuropsychological view. SCHWEI ZER ARCHIV FÜR NEUROLOGIE UND PSYCHIATRIE 156: 427-439.
An entire family of lice specializes just on carnivorous pinnipeds, (seals, walrus, and sea lions). It’s called Echinophthiriidae, and I had to memorize that name when I was in my first graduate entomology course. And, spell it correctly to get full credit on the exam.
(Why yes, 20 years later, I am still a little bitter about that. On the other hand, at important cocktail parties, I always know how to start a conversation.)
The seal louse has the wonderful species name Echinophthirius horridus; another genus is called Antarctophthirus. Like other sucking lice, they inject a little mouthtube into their host and suck their blood. They only feed on land; in the water they just hang on with their claws.
The lice in this family of insects have several special modifications from regular lice; their cuticle (waxy covering of the exoskeleton) is thicker, it traps seal sebum (body oils), and also forms scales which create a pocket of air under the oil and water for the insect to breathe while the seal is swimming.
How common are they? A 1972 study found about 75% of Northern Fur Seals had lice, and many had more than one species of seal louse. Perhaps not surprisingly, I didn’t find a more recent study in which someone closely examined 75+ seals for lice.
Clearly, there is a publication out there waiting to happen.