Tuesday, November 27, 2007

Dumbass Design™: The magicicadas

This cross-eyed critter is a cicada. Many cicada species have a yearly life cycle, but the ones we will discuss here in this installment of Dumbass Design™ are the ones that have the very long larval stage, the 13 year cicadas and the 17 year cicadas, known scientifically as magicicadas.

These critters spend the vast majority of their lives as immobile larvae at a depth of about a foot underground. They live on the root juices of plants. They aren't bothering anybody.

But every 13 to 17 years, they throw a big ass party. Here's what Wikipedia has to say.

The nymphs emerge at an evening when the soil temperature is above 17°C (63°F) and climb to a suitable place on the nearby vegetation to complete their transformation into an adult cicada. They molt one last time and then spend about six days in the leaves waiting for their exoskeleton to harden completely. Just after this final molt, the teneral adults are white, but darken within an hour.

Then the cicadas are ready for action and they start singing. What they are doing more than attracting mates is ringing the dinner bell. They don't bite or sting, and lots of other critters think the cicadas are mighty good eatin'. Any bug eating animal will feast on cicadas for the weeks that they live (and die) above ground. Even leaf eating animals will eat cicadas for a few weeks. The cicadas survival strategy is "You can't eat us all, you sumbitches!" and this is certainly the case. The survivors of the non-stop feast breed, the males are dead within hours of breeding, and the females survive long enough to lay their eggs and long process begins again.

Matty Boy, you might say! What is so Dumbass about this Design? They survive all right. My argument is that they are very susceptible to random natural disaster during their times when they are immobile. A change in the soil during the 13 to 17 years when they live underground might hit the population very hard with no chance to escape. Similarly, if there was a migration of subterranean insectivores, they would be easy pickings. A fire during the six days when they lie below the leaves waiting for the final molt could be devastating. Even after the molt, fires would hit their population a lot harder than predation can, given their numbers.

Just another example of the high risk, low reward lifestyle that we like to call Dumbass Design™.

Now playing: Bob Marley & The Wailers - Waiting In Vain
via FoxyTunes


CDP said...

The cicadas took over our neighborhood in 2004...I'm not looking forward to 2021. My son was 3 at the time and was fascinated with them...every time I did laundry, I found exoskeletons in his pockets. I shudder even now.

Splotchy said...

Why it was just months ago that my hometown's latest 17-year cicada cycle completed. I didn't know it was happening until a couple days prior (we moved here a few years ago).

There's many posts devoted to these buggers on my blog around that time. Dumbass design or not, there was plenty of them around.

Matty Boy said...

It's a very strange life cycle. Wikipedia says that they aren't much of a threat to crops except for stuff that has just been planted, but it does sound like they are a pain in the ass to be around from a human perspective. For other critters, it's a three week holiday from asking the question "What's to eat and how do I catch it?"

I can certainly understand a three year old being fascinated with this
change in the environment. I've never lived through it. Think of what a shock it must have been to new settlers in a magicicada region when the little buggers emerged.

dguzman said...

You know, I always hear about the 17-year ones, but when I was growing up in South Texas, we had them every year--so I was always confused. Thanks for informing me that there are some who do it every year. I thought I was nuts or something.

Note: we would catch these little buggers, tie a piece of thread around their thoraxes, and then let them fly around like they were on a leash.

I guess it's better than ripping their wings off, right?

No cicadas were harmed (I hope) during the making of my childhood.

Distributorcap said...

Just another example of the high risk, low reward lifestyle that we like to call Dumbass Design™.

matty can you PLEASE talk about something other than George Bush


Matty Boy said...

I actually have a post about GWB planned for tomorrow. I'm sure my new commenting friend no_slappz can't wait to correct my errors.