As the days grow shorter and colder, I find myself paying more and more attention to the organisms that I took for granted throughout the entire summer. Suddenly, cricket songs punctuate the unexpectedly chilly nights with hesitation, moths coming to the light on our deck are getting smaller and rarer, and spindly centipedes trapped in the kitchen sink in the morning remind me that I should count my arthropod blessings before winter takes most of them away.
The house centipede (Scutigera coleoptrata) is a particularly welcomed inhabitant of my domestic ecosystem. I have always been fascinated by these animals, and one of my life’s greatest achievements was the ability to convince my wife, who would rather be in the same room with a wild grizzly than a 3 mm long spider, to tolerate and (almost) appreciate their presence. On a few occasions a large centipede ran across the carpet in the living room while we watched TV, and Kristin didn’t bat an eye. (Perhaps 8 legs is that magical number that triggers irrational fear in some people – fewer than or more than 4 pairs is simply not perceived as threatening or creepy, at least not as much.)
House centipedes came to North America from the warm, Mediterranean region of Europe, where they can be found in caves and other shady, humid environments. In New England and other places with harsh winters they prefer to spend at least part of the year in houses, and live outside only during warmer summer months. This is why people generally start noticing them in the spring, when these animals look for ways to get out of the house, and then again in the fall, when they come back to spend the winter in the safety of our basements. Their presence in people’s homes is a reminder of the fact that houses are, in an essence, caves inhabited by large mammals. These mammals provide a constant stream of organic debris, which in turn supports a rich fauna of prey species for the centipedes: mites, silverfish, flies, and cockroaches, to name a few of our troglophiles.
Centipedes are the top predators of our domestic ecosystems. They are the equivalent of cheetahs in the African savanna – lean and long-legged chasers of those who scavenge our organic refuse, catching their prey and immediately killing it with one powerful bite. But their weaponry is even more sophisticated than that of the cats. Since the nervous system of insects is not as centralized as that of mammals, crushing the head of the prey would not necessarily kill it. A far more effective method is to inject the prey with venom, which instantly paralyzes it and stops it from struggling. Centipedes do so with a pair of modified legs, shaped like a pair of fangs and connected to venom glands. (Be not afraid, however – these are not capable of piercing our skin, in the unlikely event that you caught one of these things and forced it to bite you; centipedes have absolutely not interest, or capacity, to attack people.)
They also have something else that cheetahs lack – prehensile legs that can wrap around the appendages of their prey, in a way remarkably similar to that in which an octopus handles its victims. Having 15 pairs of long, grasping legs allows centipedes to carry their prey, and even hold one while hunting for another.
If you have seen these animals around your house, count yourself lucky. Their presence assures that no pest species will be able to multiply unchecked, and spread harmful germs from your trash and pipes into the rest of the house. Centipedes may not be the cuddliest of your roommates, but they pay their rent and keep the house clean.