cicada

Photo: The Star-Ledger

It has been 17 years and now a new cohort of cicadas are ready to emerge again in Paradelle.

Why? We’re not quite sure – which is one reason I am intrigued by them.

I am reading now a book on phenology, which is the study of how we can observe seasonal change in plants and animals. I am also reading a book on the daily rituals of creative people. The two books are mixing in my brain in interesting ways.

Cicadas are chirping around in my head this month too, as are the migrating red knot birds that will be coming to New Jersey to feed on the horseshoe crab eggs as those ancient creatures perform their annual ritual that is connected to the moon and tides.

I like reading and thinking about these things that scientists haven’t quite figured out. I like wondering how those migrating birds or homing pigeons find their way.  Researchers say that it seems to have something to do with magnetic fields and maybe the sun or moon. But really, we’re not completely sure. And I like that there is still that mystery to it.

With cicadas, one theory is that the cycles were a mechanism to deal with a cooling climate during the ice ages that occurred over the past several million years. Another posits the cycles are a way of avoiding predators.

Most of you probably can recognize the male cicada’s choppy, chirp, summer mating call.  I was talking to a friend about this and she said, “How can it be a 17 year cycle when I hear and see them every year?”

Good question. These particular “periodical” cicadas are different from the annual cicadas that we hear every summer. Periodical cicadas might have been called “17-year locusts” or “13-year locusts” in your neighborhood. “Locust” always suggest some plague of insects, but cicadas are not true locusts (which are a type of grasshopper).

I am writing here about the species, Magicicada.  You can spot the adults by their black bodies and bright red eyes and orange wing veins. They have a black “W” near the tips of the forewings.

In New Jersey, we commonly have the Macicada Septendecim which, like our mosquitoes, are the largest in size and have orange bands on the abdomen.

That rather ugly mating call, which some people say sounds like they are saying “pharaoh,” can get on your nerves, but is very much a sound of the start of  summer to me since they appear mostly in May and June.  Right now, soil temperatures are still in the mid-50s across New Jersey and Rutgers University reports that the cicadas are expected around the time we head to the Jersey Shore – late May.  Soil down 8 inches warms slowly and cicadas won’t be fooled by a some 70 and 80 degrees days.

2013 is expected to be one of the largest broods recorded. That excites entomologists and probably repels most of the population. I don’t find cicadas lovely, but I do find these periodical ones to be fascinating. I am imagining them underground for 13 or 17 years waiting for some signal that it is time to emerge. We know that they won’t come out this year until the soil temperature about eight inches below the surface is a nice constant 64 degrees.

But why this year? Why wait 17 years?  We are just not sure.  There are exceptions. One swarm emerged in NJ four years ago ahead of this year’s due date. We don’t know why that happened either. Scientists didn’t get to study them because they were killed off by predators before researchers could study them. It just wasn’t their time.

After they emerge from that Rip van Winkle sleep, they go through a metamorphosis just a few hours later. They go from the flightless, slow-moving nymph stage into a large, flying insect.

They try to head for the sky before predators like dogs, cats, snakes, squirrels, deer, raccoons, mice, ants, and wasps get them. Once in the air, they still have to avoid birds.

They don’t need to worry too much about people, although some people do eat them. It is said that they have a taste that is sort of asparagus and nutty and best served when they molt and are still soft.

This post duplicates most of a post from another blog of mine called Endangered New Jersey – although periodical cicadas are not endangered  they are a rather rare occurrence.  If you want to be a citizen scientist, you can report cicada spottings at magicicada.org and your data will help map where and when the cicadas emerge this year.

Another interesting citizen scientist project comes from WNYC radio and the program Radiolab (which I wrote about earlier) who have created a place online to track cicada emergence in the northeast. If you are a DIY type, you might get into building the device they describe to predict their appearance in your backyard.  See the WNYC Cicada Tracker page.

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