Monday, June 28, 2010

The Sound of Heat

Two days ago, while sitting on our back deck, I heard the first tentative sounds of summer heat. As the evening light waned, I had set down my book and was watching a swarm of dragonflies, darting above the trees. It was then that I heard the familiar buzz of cicadas, rising from the woodlot behind our home.

Likely ahead of schedule due to our exceptionally hot weather, annual cicadas generally call from July through early September. Unlike their periodic cousins, which emerge in massive numbers every 13 or 17 years (depending on the species), these "Dog Day Cicadas" crawl from the soil through the summer, usually peaking in August. It is then that their rising buzz, most prominent in the evenings, is synonymous with heat, reminding Midwesterners of our carefree, childhood summers.

Once they emerge, the adult cicadas are focused solely on producing their next generation. The noisy males attract females, mating occurs and the females lay their eggs on the tender, newly formed vegetation of trees and shrubs. The eggs may overwinter on these plants (where they are often consumed by winter songbirds) or they may hatch within a few weeks; whether they hatch in summer or spring, the larvae burrow into the soil and attach themselves to the root system of a tree, where they mature for two years before emerging. Adult cicadas, if not eaten by birds, raccoons or house cats, die soon after mating.