Earlier this year I was in the spectacular Gorongosa National Park in Mozambique, doing my usual things – chasing katydids with a net and a recorder, taking pictures, and flipping rocks. And under one of these rocks I found something that truly tested the extent of my entomological knowledge. One evening, while looking for ants and crickets on the rim of a deep limestone gorge, I lifted a big, flat boulder and underneath found a colony of termites. But something wasn’t right. Why were some of these termites longer? And wierd looking? It took me a few seconds to realize that the colony was filled with creatures that looked very much like termites, and behaved in a similar fashion, but clearly were something else.At first I couldn’t even guess what these creatures were. Mutant termites, an undescribed phylum, aliens? There were hundreds of them, easily as many as the real termites. I scooped a bunch into a container to have a closer look. OK, they were not aliens – they had mandibles and six short legs. So they were insects. But what kind? I had no idea.
Later I examined them under a microscope and saw that they had crocheted prolegs on the abdomen – so they must be caterpillars, that is moth or butterfly larvae. But they also had strange processes all along the body that looked strangely similar to candy-corn. The peculiar caterpillars turned out to be Paraclystis integer, members of the cloth-moth family (Tineidae). But what were they doing in the termite colony?
Although these caterpillars and their presence in the colonies of the termites of the genus Schedorhinotermes have been known since early 1900′s nobody really knows what the nature of the relationship between these two groups of insects is. It is tempting to speculate that the caterpillars’ strange candy-corn processes produce something that the termites like, but this is not the cases. They appear to be purely of a sensory nature and are not connected to any glands. Even more strangely, the caterpillars seem to have little tolerance for termites, and often chase them away if approached. At times, however, they allow termites to lick something from the dorsal part of their abdomen. There is one casual observation made in the late 1960′s (Harris 1968. Proc. R. ent. Soc. Lond B. 37: 103-113) suggesting that the larvae accompany the termites on their foraging trips at night, but what exactly they feed on is unknown.
I am hoping that in 2013 the mystery of the candy-corn caterpillars and termites will be one I am able to solve. And if I do, you will be first to learn about it on The Smaller Majority blog. Thanks for reading and a Happy New Year!
Winter moths are interesting animals. Unlike most species of moths and butterflies, they are strongly sexually dimorphic. In fact, while the male looks like your typical, grayish-brown geometrid moth, you will be hard pressed to recognize the female as a member of the same order of insects. She is plump and flightless, with wings reduced to tiny lobes that often resemble tufts of hair. Her mouthparts are reduced (not much to feed on for a moth at the end of November), and the only clue that she is in fact a moth comes from the scales that cover her entire body.In the coming days we will be seeing more and more mating pairs, until the arrival of permanent freezing weather kills them all off. But their eggs, safely hidden in the bark of maples that grow around our house, will hatch next spring, and thousands upon thousands of small, green caterpillars will commence their prodigious pooping on our deck at the end of April. Some years there are so many of them that the foliage of our maples is almost completely gone by the end of May. The incredible abundance of this moth is a clue to the fact that this species does not really belong here. It is an invasive species that arrived from Europe in the 1930′s, and has since spread across the entire North American continent. And because it does not have too many natural enemies here, it is able to breed in numbers higher than those of many native moths. A closely related, native species, O. bruceata, is rarely seen in similarly high densities. Winter moths (Operophtera) are not the only moths that come out around this time, and also not the only ones with remarkable morphological differences between males and females. I found another geometrid moth, the Fall Cankerworm Moth (Alsophila pometaria), yesterday on a tree trunk in Estabrook Woods. These animals are even stranger, with females completely devoid of any traces of wings, and resembling a velvet sausage running on long spindly legs.
Although winter moths are not the only insects active at this time of year, and some insects remain active even during freezing weather, their appearance reminds me of two things. First, that the insect season is truly over, and they are the last things to come to the lights of our house until spring. And second, that this Thursday night I will assume the appearance of a winter moth female, stuffed to the breaking point like a sausage, and definitely incapable of flying.