Tuesday, May 31, 2011

Periodical Cicadas II

Periodical Cicada- 17 year
I recall several returns of the 13 and 17 year periodic cicada over the years in urban settings, but I was totally unprepared for their numbers in a forest.  Walking down our tree lined drive at Bull Creek has become an almost deafening experience while wave after wave burst from the trees, colliding with me in their attempt to escape.

Ash Tree- Click to enlarge
There are two ash trees three inches in diameter beside our garage, literally covered with cicada.  They carpet the trunk, resting no less than two inches apart and hang from every branch and many of the leaves.  Standing on one spot I counted 150 on one side of a tree not including the leaves with a like number on the other side of the tree.  Three neighboring trees held similar crowds.

Walking on down the road the sound diminishes, only to pick up in another 30 feet with a similar cluster of trees loaded with cicada.  Its as though the larvae, after spending 17 lonely years underground sucking sap from tree roots are desperate for company- lots of company.  Then, as the sun disappears below the hill, the cicada disappear and there is again peace in the valley.

After several weeks of wild singing and mating, the females will leave for a little quiet time, slitting open a tree bark repeatedly to deposit clumps of eggs until 400-600 are deposited.  In 6 to 8 weeks the nymphs hatch and drop to the ground to burrow into the soil and find a juicy tree root.  In two years, 98% of them will be dead.

Cicada are on the wrong end of the fast food industry.  Nymphs are eaten by ants and underground arthropod predators like centipedes and ground beetle larvae as well as digging mammals like moles and skunks.  They also may carry the eggs of predatory wasps whose nymphs develop in their body.  Cordyceps fungi also infest them as the do ants and other insects that spend part of their lives in the soil.

Adults in large swarms are a sudden food source for birds, mammals and even a specialized wasp, the Cicada Killer.  The mass emergence of periodical cicada is a defensive strategy called by big brained bipeds "predator satiation."  What the cicada call it or if they even think about it is unknown.

Predator satiation means that when the masses appear all at once, there are more than the combined predators can eat over a short time, so many survive to breed and lay eggs.  This mass hatching strategy can also be seen with hatches of mayflies and termites.

Lots of societies around the world eat cicada.  If you are ready to try them, there are recipes for breakfast, lunch and dinner at Columbia Missourian.com

I would suggest you head for the nearest woods or tree filled park to see and hear this concert which R.L. Jacobs confirms is like Mother Nature's Led Zeppelin concert.  Its your last chance for another 17 years. 

Everything you might want to know about these cicada, known officially as Magicicada Brood XIX, can be found on this magicicada.org web site.   Who knew that they were so organized that they have their own web master?
Good general information of cicada with pictures and sound files are at umich.edu.  
There is extensive information on cicada in general at both 

1 comment:

  1. http://www.jonnecity.blogspot.com

    stories about our life :D