Oldest nest of household pest.

Oldest nest of household pest

The termits that devour the wood in your home have had millions of years of evolution to sharpen their excavating skills. In the January GEOLOGY, scientists report the oldest known evidence of termites' feasting on wood: a termite nest preserved in petrified wood, dating from the Late Cretaceous epoch (65 million to 97 million years ago). While it's not as old as the earliest known termite fossil, the nest, part of which is shown at right magnified 10 times, is "one of the earliest lines of evidence indicating the social behavior of termites," says paleontologist David M. Rohr. The recent paper was written by Rohr, John Miller and Maxine Abbott (now deceased) at Sul Ross State University in Alpine, Texas, and A.J. Boucot at Oregon State University in Corvallis.

The petrified wood containing the nest was originally discovered by Abbott last decade in Big Bend National Park in southwest Texas. According to Rohr, Abbott had noticed the small grainlike structures appearing in the wood and labeled them insect eggs. But upon closer inspection Rohr, Miller and Boucot found that most of the structures were hexagonal in shape (the photomicrograph inset at bottom right has a magnification of 47). From this distinctive shape they concluded that the structures were trace fossils of fecal pellets that had been produced by termites -- probably the forerunners of modern termites that also create hexagonal fecal pellets. Termites are the only known insects with the anatomy necessary to produce hexagonal fecal pellets, says Rohr.

Another clue that termites had done the excavation is that the nest was made in the center of the wood and the fecal pellets were distributed around the edges of the nest in the same way that modern termites use fecal pellets to plug up the edges of their excavation in order to prevent air currents from moving through the cavity.