Cranky Little Bastards

Taking stock of the centipede

 

By Constance Casey

Updated Monday, July 18, 2011, at 10:23 AM ET

 

The man who walked a cable between the two towers of the World Trade Center said he was calm and unafraid 1,638 feet above the ground, without a net.

What is Philippe Petit afraid of?

"Things with too many legs, and not enough legs." (As he told NPR's Peter Sagel.)

M. Petit was probably thinking first of spiders and snakes, but it's centipedes that go to extremes in the leg department. Eight works for spiders, two seems fine to us, so centipedes, with between 20 and 300 legs, seem to be overreaching. But their limb version came first. They're the Earth's oldest terrestrial animals, zipping around on all-hundreds for the past 450 million years.

Centipedes went the multilegged route for speed in catching prey. The showy statistic is for the house centipede—Scutigera coleoptrata—timed running at 42 centimeters per second. With a body size of just 2 centimeters, this little creature is the cheetah of arthropods. Unlike their relatively benign myriapod cousins, the millipedes, they're meat-eaters.

When they start galloping after some tasty morsel, how do they decide which leg to move first? Did some Ordovician proto-centipede obsess over the matter, and trip over its very many ankles? Like good tap dancers, the ones that survived seem to have gotten the message: Don't overthink it.

A centipede's body hangs from the legs, giving it stability. That speedy house centipede, the little one we're likely to see in the bathtub, shows this form most obviously with its 15 pairs of outrigger legs resembling false eyelashes. All centipedes' multisegmented bodies are extremely flexible, adapted for pursuing things like silverfish and termites in crevices. They're the top predator in their environment of leaf litter, earth, rotting logs, and, in the case of the house centipede, damp basements and drains.

With limbs to spare, centipedes could modify their first pair of legs into fangs. (Most poisonous creatures form their fangs from mouthparts.) These inject a paralyzing venom that contains, among its 30-some components, a kind of meat tenderizer that speeds the paralyzing effect and softens up the prey. As Greg Edgecombe, resident centipede maven at the Natural History Museum in London, put it so vividly, "They homogenize the contents and slurp it out like soup."

Centipedes eat various insects, plus worms, spiders, and, sorry, other centipedes. But New Yorkers take note: They also eat cockroaches and bedbugs. Though the fangs of the house centipede, and most of the other small ones, can't pierce human skin, it would take a very tough city dweller to welcome a centipede into bed. (Related cultural note: Rebbie Jackson, elder sister of Michael, made a music video of the song "Centipede," co-starring a tiger, a cobra, and a chorus of young men in black tie. Informed sources say the title refers not to the myriapod but to an orgy involving 100 people. A less cheery, truly gross pop culture phenomenon—the movies Human Centipede and Human Centipede 2—demonstrates that evolution is a lot better than a mad scientist when it comes to creating viable, many-legged creatures.) [Source: www.Slate.com]