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Cicada Shell (4)
tuslaw
![Gold Star Critiquer/Gold Note Writer [C: 252 W: 8 N: 682]](http://i1.treknature.com/misc/g-n-g.gif) (2217) | The Cicada hatch this year has been rather large in our area of Ohio. Every day I can walk out back and find these empty shells clinging to the sides of the trees. My grandson Travis is getting pretty good at spotting them as we take our nature walks through the back yard.
You can hear the buzzing sounds of the cicadas all day long, at times the noise almost seems deafening. The southern part of Ohio has been especially hit hard with their emergence.
I remember years when they were so numerous that you would see hundreds of these empty shell casings scattered on the forest floor. While driving down the interstate you could roll down the car window and for miles hear their constant buzzing calls.
I will post another photo of one of the empty shell casings in the workshop if you care to view it.
Tibicen Canicularis (Dog Day Cicada)
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).
A small number of cicada species have synchronized their life cycles so that they emerge from the ground in their billions only once in every 13 or 17 years. These are known as periodical cicadas but are also commonly called 17-year cicadas, 13-year cicadas, or locusts. They are not locusts, however. The dog-day cicada is dark with green markings. The periodical cicada has protruding red eyes and orange legs; adults have clear wings with orange veins. 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).
Once the predators have eaten to capacity, there are still millions of cicadas left over to produce the next generation. Predator populations cannot build up in response to such a massive food supply, because the cicadas appear above the ground only once in every 13 or 17 years.
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.
Magicicada cicadas synchronize their life cycles only in local areas. 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.
Information from: Free Wikipedia Encyclopedia |
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