Winter moths

In early to mid November, after most of the night-flying moths have succumbed to the first hard frosts, a newcomer arrives, often in great numbers, at the back-porch lights. These remarkably cold-hardy lepidopterans are known as winter moths, and they're a genuine problem. Operophtera brumata, a member of the Geometrid family, was inadvertently introduced into this country from Europe in the 1950s. While the species is not quite the large-scale defoliator that the Gypsy Moth was before a fungus started to bring that pest under control, the winter moth can do a lot of damage when its caterpillars emerge in the spring to devour new foliage. Right now, O. brumata is courting—only the males can fly; the females, resting on tree bark, emit pheromones that their swains will follow—and because there are almost no predators interested in eating them, the insects can bulid up huge populations. Ordinarily, I'd look at this congregation of deceptively fragile moths with a measure of respect, but when I think about the havoc their youngsters may wreak during the growing season, I greet the influx with dread—and thoughts of reaching for pesticides.