The 17-Year Itch
Brood X reappears, with clues to cicada behavior
By Tabitha M. Powledge

>From late May through June, Brood X of the periodical cicadas will emerge
from the ground, having spent the past 17 years as nymphs feeding off tree
roots. After digging their way out and molting into adults, billions of the
big, clumsy, red-eyed insects will sing their earsplitting love songs. Last
seen in 1987, the brood will provide a prodigious if brief feast for birds,
along with an incomparable opportunity for researchers. Fascinated
naturalists have been writing about periodical cicadas for four centuries.
But much remains unknown about the insects' periods or what triggers their
synchronized appearances.

Brood X is perhaps the largest and best studied of the approximately 15
broods of periodical cicadas (researchers dispute the exact number). A brood
emerges somewhere east of the Great Plains almost every spring. Worldwide,
investigators have identified some 3,000 cicada species but know the life
cycle for only a dozen or so. William Bradford, governor of the Plymouth
Colony, first described periodical cicadas in 1633, although Native
Americans probably knew of the creatures before then. The 17-year life cycle
was firmly established less than a century later; by the mid-19th century,
naturalists had recognized 13-year cicadas.

Read the rest at Scientific American
http://cl.extm.us/?fe9413737062047b75-fe3016707360067c711779

Posted by
Robert Karl Stonjek.
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