House Centipede


(This 947th Buffalo Sunday News column was first published on May 17, 2009.)



House Centipede


"Get down here quick," my wife called up to me from the basement. I know that tone of voice so I hustled down to see what she wanted.


"See it." She pointed at the top of her enameled washer. "Look at all those legs. There must be hundreds of them."


Just in time, I saw a little inch-long arthropod dash over the edge of washer and out of sight. Doris's estimate of the number of legs was a bit high, but she had the same idea as whoever named the little beast. It was a centipede. Even if that centipede had been a two-inch long full adult it would have had only 15 pairs of legs. Together with its two longer antennae that would only total 32 appendages.


You'll notice that I said arthropod and not insect for insects have only six legs. Spiders have eight so this was not one of them either. An arthropod, according to my dictionary, is any invertebrate of the phylum Arthropoda, having a segmented body, jointed limbs, and usually a chitinous shell that undergoes moltings, including the insects, spiders and other arachnids, crustaceans, and myriapods.


In fact, centipedes belong to a class of arthropods called Chilopoda all by themselves. They are easy to distinguish, the gray bodies of adults have three darker lines running their length. On an immature like the one my wife showed me those lines are not as striking, but its legs were a giveaway. The house centipede's hair-thin legs are almost half as long as its body. In fact the antennae and hind legs are still longer.


The reach of these appendages give the tiny arthropod the appearance of being much larger than it is. Its spreading legs cover an elliptical area as wide as its torso and half again as long.


When the centipede is still, the similarity of its long antennae and equally long hind legs make it difficult to tell which end is which. You have to look closely to see the bulging eyes with a darker spot behind each one to identify the head. Unless you find one of these little beasts in a bathtub or sink from which it cannot escape, you won't have a chance to make such observations because they move too quickly. However, other evidence – the direction in which it moves, for example – will quickly identify its orientation.


This is indeed a fast insect. Observers have recorded it moving 16 inches per second. That is eight times its length in a second. How many of us can move that fast? Work it out and you will find that, relative to their size, not even the world's finest sprinters could match it.


My wife is not a bug-lover, but she ought to like this centipede. It is a very beneficial predator, capturing and eating insects and spiders. Centipedes have well-developed eyes but, since they mostly hunt at night, they rely more on their sensitive antennae that not only feel but also detect odors.


They capture their prey by pouncing on it or in effect lassoing it with those long legs. They will even capture more than one insect at a time, feeding on one while their legs hold another to serve as dessert.


Centipedes are aggressive predators but they are especially careful around poisonous spiders and insects. They may simply avoid insects like wasps, but they can deal with a spider by quickly biting it to release its own venom and then backing off until the venom takes effect.


We need have little fear of their biting us because their jaws are not strong enough to break our skin. Even if we were bitten, however, the effect would be minor pain and swelling.


Indoors, centipedes are most often found in damp areas: dark basement corners or occasionally in a sink or tub. Outside they are very common but seldom seen.


The centipede is the butt of a story that takes several forms. My favorite is offered in the form of a poem by entomologist May Berenbaum:


A centipede was happy quite,

Until a frog in fun

Said, "Pray which leg comes after which?"

This raised her mind to such a pitch,

She lay distracted in a ditch

Considering how to run.

-- Gerry Rising