Prime Numbers

Today was a big trip out for me. I have been somewhat couch-ed by a back injury (not something I recommend if you are planning a trip to Europe but hey) and haven’t wandered far from the back patio since my U.S. homecoming.

But I seem to be getting better, and today I went out early with big plans to document the walnuts and hickory nuts that are getting… nutty. However I was distracted by some insects and this blog’s motto is Be Where the Creepers Are (warning: not applicable in social scenarios). So that is where I went.
Recently my Dad dragged me outside to look at a cicada. What? I like big bugs and I cannot lie. It was the first one I’d seen this year although I have been hearing them since mid-July. Today I reached out to open a gate and nearly crunched this little thang right here.Image
They’re heeeeere. And not the nutso epidemic variety. This is the run of the mill see them every fall regular version that does not invite its whole species to a once every 17 year month-long sex party. These are the guys I can thank for the sweet seasonal sounds of home. They belong most likely to the genus Tibicen and you probably noticed their life-like but distinctly dirt colored empty shells clinging to trees you climbed when school was starting or in other places with a nice grasping surface above some delicious sap-filled roots. Oaks, Willows, Ashes, and Cyprus are popular choices with I guess extra sweet juiciness for the nymphs to eat during their underground childhood. The annual cicada apparently spends about 2-3 years as a sweet little nymph down there, with a bunch popping up to mature every fall.
When that happens, they burrow upwards in their final nymph body stage, often leaving a dime-sized hole in the ground, and crawl to a good spot for shedding, leaving their juvenile wingless selves behind.
ImageIn my imagination this happens in the late night and early morning, possibly because I have never witnessed it. The back splits open down the middle and the winged adult emerges. I was busy trying to get my iPhone to focus on the shell and not on the deck behind it when lo I noticed someone watching me:
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I think this is the actual adult that came out of the shell! Pretty winged thing. Maybe she is just waiting to warm up before she joins her friends who were making a racket as I stood there. She held very still until my camera’s shadow fell on her at which point she flexed a wing, stretched a leg and walked back into the sun. I was glad to see her and hope she avoids being eaten by squirrels, birds, the horrifying Cicada Killer Wasp, or worst of all, a hipster.
Experts can distinguish the approximately 32 Tibicen species by their sound. I am not quite on that level at the moment. But my Mom saw this lady and declared that her big brown (green though Mom?) eyes certainly did not belong to the every 17 year cicada. Those are from the genus Magicicada and they have creepy bright red eyes. They come out in the spring every 13 or 17 years. Although there was a lot of fuss about their possible appearance in May, I did not expect to see them. They were here in 2004 don’t you remember? Truth be told there are a lot of different broods. Allegedly 11 17-year and 4 13-year groups with 1 now believed to be extinct. The NYTimes posted a great video mapping them out. There are cyclical cicadas coming out almost every year in different parts of the East Coast. Brood X is the one that I’ve seen come around twice now, and apparently Brood II is the one that inspired all the buzz in the yards of our neighboring states this year.
In looking into the Cicadas on the internet, I found a LOT of references that were sort of? jokes about ways to eat cicadas. Could this be the gateway insect to live up to the UN’s recommendation that we make bugs a regular source of dietary protein? Meatless Mondays, Thorax Thursdays? #glutenfree. In 2004 when Maryland had the last major Cicada swarmage I was taking a Wilderness First Responder Class in College Park. We did a lot of our practical scenarios in the gravel under the climbing wall. For the first few days there were piles of crawling Cicadas covering the ground but by the end of the week they were mostly just making a racket from up in the trees. My friend grilled and chocolate dipped a few but it turned out he had unwisely used dead ones so nobody ate them. I also remember being really into my Bob Dylan cd at that time.
These creepers were no fools by the way when it came to choosing 17 and 13 for their cycle. While hipsters may not have impacted the reproductive success of the Magicicadas through predation (yet!), predators can really mess shizz up for an insect trying to find a mate and make some babies. Coming out in huge numbers all at once is one way to improve outcomes, by overwhelming the predators in sheer number. Lots of animals (and plants!) use this strategy. By evolving to have prime numbers for their reunion years, the odds that any predator (or any other brood of cicadas for better or worse) will match its schedule up with them and have lots of its own babies to eat everyone in the swarm are virtually eliminated. Math in nature is kind of neat.
More neat things can be found in the Emergence podcast that Radiolab replayed in honor of the cicada hysteria this year.
Here I am in I assume 1987, delighted to find bugs that showed no fear of me when I held them. See your grandchildren in 2021 buddy.
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 (also pictured: Rascal, turtle shell, my adult thumb)
Nuttier tales to be covered soon.
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3 Comments

Filed under Insects!, Seasons

3 responses to “Prime Numbers

  1. Amelia

    This was an awesome post for me because I love cicadas! I also remember when they were in college park back in 2004. Also that summer, I worked at summer camp in western md and someone in the kitchen made one of the staff a cicada pancake!

  2. Jody

    This was very informative. The added music video, cicada brood layout, and edible bugs sheet were great additions!

  3. Oh my gosh Amelia I forgot about your camp, but now I remember it being a frequent topic of conversation back in the day. I am happy you also love cicadas! Jody thank you, are there many cicadas in Wisconsin? I am glad you discovered the Lord Huron link ;-).

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