In May, cicada nymphs will appear by the handful in areas treated to Brood II.
News came last week that somewhere in Stokes County, NC, Brood II cicadas were seen. In parts of Stokes County, growing degree days from January 1, 2013 have exceeded 360 and this seems to be warm enough to convince these teenagers that the time has come to greet the sun. Like a huge tsunami, this exodus will continue to roll up the eastern seaboard from North Carolina to the Hudson Valley in New York and eastward to central Connecticut as the warmth of spring extends its northern reach. In the path of this biological deluge are major metropolitan areas and their suburbs including Hartford, New Haven, New York City, Philadelphia, and southern suburbs of Washington, DC. One report has it that periodical cicadas may even be seen in Central Park, NY.
Where cicadas are present, hundreds of exit holes and mud turrets can be found under leaf litter beneath trees.
Newly molted cicadas are spectacularly beautiful but extremely vulnerable to predators.
As a child growing up in Morris County, New Jersey, I fondly recall the appearance of Brood II in 1962 and the adolescent hysteria it created on the playground where my classmates feigned bravado or openly shrank in terror from the noisy horde. Nymphs have been feeding underground on xylem fluid from plant roots for the past seventeen years. This dismal existence is about to come to a screeching end. Over the past several weeks, nymphs constructed escape tunnels to the surface of the earth. Soil temperatures in the middle sixties are the cue that the world above ground is warm enough to support flight, escape from predators, and reproduction. Many nymphs emerge at night and make a mad dash for vertical structures such as trees and shrubs whereupon to make the final molt to adulthood; however, lampposts, street signs, and slowly moving people seem to work just as well. After climbing up and away from the soil, they attach to a firm object to begin the process of molting. Their outer skin, or exoskeleton, splits along a predetermined line on their back and the beautiful adult cicada wiggles free from the shell. The freshly molted adult is almost pure white except for bright red eyes and patches of black behind the head. Before the exoskeleton hardens, the cicada must expand its wings or it will be unable to fly and seek a mate. After wings and legs have hardened, cicadas scurry or fly to the treetops where courting, mating, and egg laying occur. The visit of the periodical cicadas above ground will be short, and by the end of June their carcasses will return to the earth and fertilize the roots of the trees from which they spawned. What a curious and marvelous turn in the revolving circle of life.
My friends in Washington DC area have asked if they will enjoy a visit by cicadas this year. One map listed below holds some hope that Brood II may appear near the district. However, cicada guru John Zyla has produced a wonderful cicada map for our region that puts the nearest emergences of Brood II in Calvert, St. Mary’s, Fairfax, Fauquier, and Prince William Counties. This map can be found at the link below. Over the past several weeks, I have investigated several potential sightings of cicadas in Anne Arundel and Calvert Counties in Maryland and come up empty. Several reports of “numerous holes” in the ground were actually galleries constructed by ground nesting solitary bees.
This little cicada has a couple weeks to go before she makes her grand appearance.
Earlier this spring, I and one of my colleagues were fooled by the call of an amphibian that sounded surprisingly reminiscent of a cicada song. However, at one site in St. Mary’s County, I recently discovered a soggy woodlot loaded with Brood II nymphs. As of last week, these little rascals were still deep in their burrows and had yet to develop the dark patch of color just behind their head that signals their imminent emergence from the earth. My best guess is that the exodus from below is still a couple of weeks down the road. This schedule fits well with the last brood of cicadas to emerge in St. Mary’s County, Brood XIX, which appeared in the latter half of May in 2011 (see St. Mary’s Survivors, June 6, 2011). I fear that DC, Montgomery, and Prince George’s are out of luck this time for enjoying cicadas in the back yard, but who knows, maybe the cicadas will deliver us a surprise. Nonetheless, as these marvelous creatures make their presence known, it will be well worth a trip to a nearby location to witness this remarkable event.
References
This episode was inspired by Deak and Sheri, who lead the discovery of the Far Hills cicadas. The wonderful article by K. S. Williams and C. Simon “The ecology, behavior, and evolution of periodical cicadas” was used as a resource for this episode.
To see John Zyla’s cicada map and other cicada maps, please click on the following links:
http://www.magicicada.org/about/brood_pages/broodII.php
http://www.cicadamania.com/pictures/main.php?g2_itemId=3618
To learn more about periodical cicadas and cicadas in general, please visit the following excellent web sites:
http://insects.ummz.lsa.umich.edu/fauna/michigan_cicadas/Periodical/Index.html
http://www.cicadamania.com/cicadas/category/broods/brood-ii/