They’re baaaack...

By "Tern" Jess Leber
All over the east this month, nature enthusiasts are listening to their songs, mapping their sightings, and debating which species are where. One web community is offering a reward for the rare few with white eyes. Scientists who study them are busy seizing a once in a 17-year opportunity. Even outdoor wedding planners are taking note.

No, the fuss isn't about some unusual bird but, rather, a rare bird food: a group of cicadas called Magicicada. In appearance, these disconcertingly large and wide-eyed winged insects aren’t much to speak of. But their group-think life cycle is something else.

For 16 years they live as nymphs in underground burrows, surviving on plant roots. In the spring of their 17th year, they swarm into the sun en masse where they molt, sing, mate and lay their eggs only to die four to six weeks later. And unlike their annual counterparts, periodical cicadas complete their life cycle in unison. The 2008 cicada class, known as Brood XIV, won’t be seen again until 2025. You can spot its members now, as they deafen 13 states with their buzz in May and June. There are another 11 broods of 17-year cycle cicadas and 3 broods of 13-year cycle cicadas, but all have different ranges. The next brood, the 13-year variety, isn't due to invade until 2011.

The cicadas' strategy—sex in infrequent swarms—is relatively unique in nature, according to Michael Stroh’s interesting article in the Baltimore Sun exploring why such a behavior may have evolved. In 1977, biologist Stephen Jay Gould proposed that by appearing in overwhelming numbers, the cicadas quickly satiate their predators' hunger, leaving the rest of the bugs safer to mate in peace. The cicadas’ oddly-timed cycles may also minimize the chance that their appearance coincides with peaks in the life cycles of birds and other predators. Recently, one scientist built a mathematical model which supports this idea, while others believe that different variables, such as past climate, may have influenced the cicadas' evolution.

As for the numbers 13 or 17…that’s still a big mystery. But whether or not you live in the path of the current invasion, it’s worth taking a closer look at their show. Here’s a time-lapsed video that captures the last weeks of their time on earth.