Here’s the scoop on the little buggers.
I remember them well from my youth, circa 1962. In the well-arbored suburbs of New York and New Jersey, they sang in the trees and then carpeted the ground like fallen leaves in autumn, making an ominous crunching sound as one walked, the whole extravaganza a sort of cicadesque supernova explosion that signified their own demise and the launching of the next generation into subterranean abodes where they would hang out for the next seventeen years.
Adult periodical cicadas live only for a few weeks—by mid-July, all have disappeared. Their short adult life has one purpose: reproduction. The males “sing” a species-specific mating song; like other cicadas, they produce loud sounds using their tymbals. Singing males of a single Magicicada species form aggregations (choruses) that are sexually attractive to females. Males in these choruses alternate bouts of singing with short flights from tree to tree in search of receptive females. Most matings occur in “chorus” trees.
Receptive females respond to the calls of conspecific males with timed wing-flicks, which attract the males for mating. The sounds of a “chorus”—a group of males—can be deafening and reach 100 dB. In addition to their “calling” or “congregating” song, males produce a distinctive courtship song when approaching an individual female.
And here, if you’re feeling like participating in the fun, is a video. It’s not Brood II, but it’s a similar brood of 17-year lovelies from Illinois: