Ticked off

14 05 2007

Every once in a while something happens that causes little flurries of thought in my head, and such was the case when I decided to take a hike through a section of the Appalachian Trail that runs through the Delaware Water Gap this past Saturday. As I made my way up the hillside, keeping my eyes open for interesting arthoropods and (if I was lucky) mammals, I felt something crawling up the back of my leg. When I stopped I discovered that it was an American Dog Tick (Dermacentor variabilis), trying to make its way to warmer regions. I promptly flicked it off (another one attached itself to me moments later and received the same send-off), but after doing so it struck me that I detected its presence because it was moving the hairs on my legs as it crawled along. I certainly didn’t feel it on my skin, but as it climbed over and pushed aside the hairs on my legs I detected the presence of the little arachnid.

There is some debate as to why we humans have rather sparse body hair. Some believe that it’s in response to the warm climate in which we originated (the Savanna hypothesis), others regard it as a sign of human ancestors once living in water (the Aquatic Ape hypothesis), yet others proposing that it was part of Fisherian runaway sexual selection. The first two are especially contentious and the issue will likely still be debated for some time, but struck me is that if there was some reason that we should lose most of our hair, why didn’t that trend continue? What advantage would there be to being at least partially hairy? Hair serves many functions in keeping unwanted foreign objects like dirt, sand, etc. out of important sensory organs and orifices, but what about our legs? Could it be that we still have relatively hairy extremities because of selection caused by insects that spread disease? To test this we could find some participants of varying hairiness and put ticks on their arms/legs (watching that the little blighters didn’t get away and tuck in, of course) and see if some people are better at detecting them than others. Someone who shaved arms/legs would have to be tested as well, of course.

I could be entirely wrong in my hypothesis and it could be entirely baseless, but I think the role of disease-spreading insects has been largely overlooked when it comes to human evolution (there are exceptions of course, like this recent research). A lot of attention is paid to giant hyena or saber-toothed cats, but I doubt they killed as many humans as disease did, and maybe hair had something to do with who survived and who did not, perhaps even mitigating runaway sexual selection. As I stated before, this is merely blind hypothesis based upon a walk through the woods, but it does make me wonder about the intricacies of our own evolutionary history.

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Because I got high…

11 04 2007

Yesterday I posted about how eating fructose-laden fruits helps bats deal with ingesting ethanol (drinking alcoholo) in ripening figs and dates, as well as other animals that have been known to get intoxicated from time to time. For those of you who’ve never seen it, I’ve managed to find a video snippet featuring a lemur and giant millipede in Madagascar (where else would a lemur be?), illustrating that humans aren’t the only ones who like to get high;

Is anyone else a little put-off by the way the clip was narrated? Besides the “trippy” camerawork, the almost menacing tone of the narrator seemed a little over the top, especially when he asserted that the lemurs are “millipede junkies” always on the lookout for their next fix. How often these lemurs engage in this behavior, I honestly don’t know, but I can’t help but wonder if they are being made out to be hopelessly addicted to the millipedes for the sake of amping up the drama.





Hooray for giant fish monsters!

2 03 2007

I hadn’t heard about it until yesterday, but apparently there’s an award-winning South Korean “revenge of nature” horror flick lumbering towards the US – The Host. This one looks like a real treat; check it out for yourself below

From what I understand, the effects were done by Weta and the folks who did Harry Potter and the Goblet of Fire, the monster getting plenty of screentime right from the start, so there will be none of the “Let’s hide the creature from the audience for an hour and a half and let them down with something that looks like a slimy salami in the last 15 minutes” business. What’s even more interesting is that the movie based on a US army personnel member dumping 227 liters of formaldehyde into a river, the film following in the footsteps of Godzilla and Alligator in using a man-munching beastie to convey an ecological theme. Unfortunately the closes the film is coming to me is Elizabeth, NJ, but hopefully it will get a wider release if I can’t see it when it first gobbles up the local screens.





Something new in the Grand Canyon

1 03 2007

According to this LiveScience article, a new genus of “albino” millipedes (comprising two species from two distinct locations) has been discovered in the Grand Canyon. Here’s a shot of the newly discovered critter;

millepede

The same group that investigated the caves that brought the millipedes to the attention of science also discovered new species of spider, barklouse, beetle, possibly two springtails, and a new genus of cricket, so between this and the discoveries being made in the Pacific and Antarctic waters, there’s plenty of new critters to study and describe these days. It is important to note, however, that it’s a misnomer to call the millipedes albino; true albinism being a recessive genetic disorder and not an adaptation to life in leaf litter, as J. Judson Wynne correctly pointed out (thanks for the clarification!) .