February, 2009

Prairie Alligator

Most of our stick insects, or walkingsticks, belong to the family Diapheromeridae. These are very slender and well-camouflaged vegetarians, never particularly numerous. There is one kind of walkingstick, though, that is a bit different. The prairie alligator (Anisomorpha ferruginea) is much more stout and in the family Pseudophasmatidae. There is one other related species called the two-striped walkingstick, found in Florida and the southeastern part of the U.S. These two species look similar and have a variety of other common names, including musk-mare and devil rider, which refer to the habit of the much smaller male clinging for long periods to the back of the female while they mate. The pictured insect here is a female, measuring about 3 inches in length.

Most stick insects have no defense other than their camouflage, but the prairie alligator has another trick up its sleeve. It is capable of squirting a smelly liquid containing chemicals called terpenes out of glands located just behind its head. Although I've handled several of these insects, I've never experienced that reaction. There is, however, ample documentation of this phenomenon, including the effect of causing severe irritation and even temporary blindness if it contacts the eyes. And the insect does shoot for the eyes of a perceived attacker. Its aim is quite good and it can direct the spray up to about two feet away.