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Periodic Cicada -
Magiciada sp. |
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| 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). |
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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. |
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Exuvia (plural: exuviae) (castoff skin after molting) includes
exoskeleton and
coverings for the nascent wings, compound eyes,
extremities, as well as setae.
