Tuesday, December 31, 2013

Cicadas, Every 17th Year



It is the time in our year when we think about annual cycles.  But this summer we were reminded of longer life cycles:  The cicadas came back this past May, and stayed through June.  The last time we had seen them, Rebecca was six years old, and Sarah was 3.  Over a course of weeks we saw large numbers of these strange creatures crawl out of the ground (leaving half-inch holes), cling to grasses and small shrubs, shed their shells, and fly up into the trees.



These are the "periodical cicadas" (cicada septemdecim) which have a seventeen year life cycle, most of which is spent underground.  We went out at night with flashlights to see the nymphs emerging from the ground and crawling in large numbers.  Some shed their shells quickly, leaving large numbers of the husks in their wake.


The cicadas were everywhere.  We saw from maps online that North Guilford, Connecticut was one of the "hot spots" of this brood of East Coast cicadas (there are different broods of periodical cicadas that come up in different locations around the world; ours is "Brood II").



I read that there are several related sub-species that co-exist; we weren't sure we were seeing different "looks" of the emerging cicadas because we were seeing cicadas at slightly different moments after their emergence, or whether we were seeing different sub-species.  But all had the same mysterious red eyes and beautiful wings, and soon after being able to fly they started to sing.  Loudly.


Brood II sang constantly for weeks.  When you went outside, you couldn't hear birds or other normal sounds; all you heard was the singing of the cicadas.  (We had remembered the prior emergence being so loud that we had to shout to be heard in our back yard.  This year's wasn't quite so loud, and we weren't sure whether over seventeen years our memories had become exaggerated.)

Our neighbor Brad noticed that as the cicadas' chorus quieted, small branches started to litter the ground.  He showed us a scoring pattern along the stem, where the females have cut slits to lay their eggs.


The physical aspects of the cidadas are surprising and beautiful.  But it's their sound that is for me most magical.  The chorus is a mass of courtship songs, and they are singing for each other.  We are privileged to be able to be at the right spot, at the right time, to hear their music every seventeen years.  

If you want to hear what our back yard sounded like in June, click on the video below.



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