Even though the arrival of spring is officially not for another two weeks, the change of season is already palpable as wildlife stirs from winter's scarcity, birds begin arriving from southern wintering grounds, and trees begin their spring blossoming. It's likely to be a noisier spring than usual, too, for a rare event is about to take place - the simultaneous emergence of two broods of periodic cicadas, something that hasn't happened since 1803, when Thomas Jefferson was president.
The two broods that will emerge late this month or early in April are known as Brood XIX, which will emerge in the Southeast, and Brood XIII which will appear in northern Illinois. Other broods will take their turn next year, usually just one brood per year, but every 221 years, two broods will emerge at the same time, much to the excitement of entomologists. One such scientist - Charles Marlatt, who worked for the Department of Agriculture in Washington - was the first to standardize brood numbers in 1893, designating all cicadas emerging that year and every seventeen years thereafter as Brood I; those emerging the next year were Brood II, and so on. Cicadas on the thirteen-year cycle who emerged in 1894 were Brood XVIII. It's Brood XIX, first designated as such in 1895, that is emerging in the Southeast this spring.
These harmless insects have an unusual life cycle. Immature cicadas, or nymphs, spend the next 17 or 13 years after hatching underground feeding on roots, emerging from the earth as adults after more than a decade hidden from view. The males are the singers, attracting mates with sound-producing organs called tymbals on either side of their abdomens. Adults don't consume solid food, but subsist on on fluids from leaves and tree bark. Females lay their eggs in the bark of trees, which can be harmful to young saplings but otherwise doesn't hurt mature trees. Cicadas don't sting or bite and are not known to carry diseases harmful to humans.
They are, in fact, beneficial to the ecology. Their underground tunneling aerates soil, and once above ground, they serve as an important food source for birds and other wildlife - and for humans in some cultures, where they're consumed fried or steamed and are said to taste like cold canned asparagus. But if you choose not to partake, you can at least enjoy the singing on a warm Lowcountry spring evening.