|Annual Cicada – Tibicen linnei|
Suborder Auchenorrhyncha / Family Cicadidae
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Live adult cicadas photographed in the wild at DuPage County, Illinois
There are about 2,000 species of cicadas worldwide, most of them found in tropical or temperate regions. Most of the more than 100 species found in North America have short life cycles, between two and eight years. They are known as annual or dog-day cicadas because they usually emerge during mid to late summer (July and August).
It is not known how periodical cicadas synchronize their life cycles over 13 or 17 years, or how they manage to count out the years. But by emerging at such long intervals in such vast numbers, as many as 1.5 million insects per acre, according to one estimate, they have evolved an effective strategy to overwhelm predators by sheer volume. The mass emergence of periodical cicadas provides an unlimited feast for birds, snakes, and mammals. Even humans have been known to eat the harmless insects. (Cicadas are not poisonous and do not bite or sting).
There are 12 broods, or year classes, among the 17-year cicadas and three broods of 13-year cicadas so that in almost any given year it is possible to find adult periodic cicadas somewhere in the U.S.. The significance of 17 and 13 is their being prime numbers; would-be predators’ life cycles, be they even or odd years cannot match the prime number of years.
The emergence of 17-year periodic cicada, Magicicada sp. brood XIII, in 2007, near Chicago, was a sight (and sound!) to behold. Yet there were areas of the Chicago suburbs that had nearly none, others were overwhelmed and the insects crunched underfoot on the sidewalks! The din at the Morton Arboretum, near Lisle was incredible.
Periodic cicadas are found in eastern North America and belong to the genus Magicicada. There are seven species, four with 13-year life cycles, and three with 17-year cycles. The three 17-year species are generally northern in distribution, while the 13-year species are generally southern and midwestern. Periodic cicadas generally emerge in May and June, apparently when the soil temperature reaches 64° Fahrenheit (18° Celsius). This means that emergences in southern and low-lying areas occur earlier in the summer than in the cooler northern locations.
Order Hemiptera: True Bugs number almost 5,000 species in North America, and 40,000 worldwide. They have mouthparts formed into a beak, adapted for sucking plant juices or the liquefied insides of their animal prey.
Suborder Auchenorrhyncha – Cicadas & Planthoppers
Suborder Sternorrhyncha – Aphids, scales, mealybugs, jumping plant lice.