Recently on my way home from class I was startled when a very loud, large bug flew by. When this bug landed, I was further startled by the fact that it was a cicada. I remembered from a previous science class that cicadas are periodic creatures that live most of their lives underground in a nymph stage only emerging every 7 years or so to reproduce. Based on what I had learned I assumed every 7 years would be a so called "cicada year" where large numbers matured at once, and you would be unable to find a mature cicada on the other years. For this reason I was shocked that sitting there before me was a cicada only 5 years from the last time I've seen one.
Little did I know that I was only half right. You see Florida is home to only non-periodical cicadas, mostly of the Tibicen, Diceroprocta, or Melampsalta genera. Since their maturation is not synchronized mature cicadas can be found every year, though they are seldom seen or captured. Different species emerge at different times of the year. Please see the table at the side of the blog to learn more about the time of the year that adults of each species can be found in Florida. Little is known about the length of their life cycles, but it is generally estimated to be 6-8 years, of which my previous assumption of 7 years is a good average. Outside of length, their life cycle is the same as the periodical cicadas.
The periodical cicada is of the genus Magicicada and has a 13-year or 17-year life cycle. Magicicada is native to the northeastern region of North America, only ranging as far south as Georgia. The maturation of these periodic cicadas is synchronized, meaning that large numbers mature all at once resulting in the above mentioned "cicada years". This adaptation actually acts as a defense mechanism, since predators are able to eat their fill without significantly reducing the population. This is referred to as predator satiation. http://insects.ummz.lsa.umich.edu/fauna/Michigan_Cicadas/Periodical/Index.html gives a list of Magicicada broods, regions, and years of maturation.
Cicada's spend most of their lives underground as nymphs, feeding on the sap of roots. It will also molt four times while underground. A few weeks before the end of their life cycle they emerge and climb a nearby tree or shrub where it will molt for the last time, emerging as a mostly white adult. As their exoskeleton hardens they darken and their wings become stronger. As adults they spend most of their time in the trees calling for a mate. The calls made by the males are often used to identify different cicada species. Male cicadas produce their calls with timbals or drum-like structures on the sides of their abdomen to attract a female. A female may respond by making a clicking sound with her wings. When male finds a female it will switch to a quieter courtship calling pattern. The male and female mate, then the female deposits in slits she has made in small branches, twigs, or rarely grasses. In a few weeks the eggs hatch and the nymphs drop to the ground where they begin their lives underground.You can check out the youtube video in my second post to learn more about the periodic cicada's life cycle.
References:
http://insects.ummz.lsa.umich.edu/fauna/Michigan_Cicadas/Periodical/Index.html
http://entnemdept.ufl.edu/creatures/misc/bugs/cicadas.htm#life
http://entnemdept.ufl.edu/walker/buzz/c700fl2.htm
The Southern Dog Day Cicada (tibicen davisi)
This is the type of cicada I spotted on my way home. This species of cicada (tibicen davisi) is native to Florida and has a life span of 6-8 years. Unlike the periodic 13-year or 17-year cicadas of northern regions, the maturation of this species is not syncronized.
