Wednesday, June 1, 2011

The Great Southern Brood Returns

My neighborhood is currently dealing with an infestation of thirteen year Magicicada cicadas. Most of the older folks around here like to refer to them as "the thirteen year locusts", but, the truth is, cicadas aren't locusts. They sure seem to swarm like locusts, though. They're all over the place, crawling up trees, hiding among the flowers and attaching themselves to the side of all the houses in the neighborhood. The other day, while riding around the block on her bike, a number of them jumped on my daughter, scaring the bejesus out of her. It wasn't a huge deal, because they don't sting or bite, they just swarm and make loud noises. Still, the kiddo became rather apprehensive about going near them, so I decided to turn it into a science lesson for her in the hopes that she'd get over her fear of them.

Cicada Nymph
I explained to my daughter about the cicada life cycle, how they burrow underground as nymphs and stay there for thirteen years. While they are underground, they feed on root juice and dig around with their strong legs. When a cicada emerges, it crawls up the nearest tree and begins the molting process. The cicada splits out of its exoskeleton and flies off to mate and eventually die. Having stored up much of its nourishment over its thirteen years as a nymph, the adult cicada is more interested in mating than it is in eating, although it does have structures that can tap into tree sap. In its final, winged form, the cicada buzzes by flexing its tymbal muscles which produces a clicking sound as the tymbal membrane vibrates. This noise making method differs from the cricket which uses stridulation, a method of rubbing one body part against another to make sounds. These sounds have a number of different uses, but a cicada generally buzzes in order to attract a mate. Once they mate, they die, but not before the female lays several hundred eggs inside the bark of a tree branch. Cicada carcasses, as well as discarded nymph exoskeletons make great fertilizing material. 

My daughter seemed to enjoy the science lesson as it involved us studying nymphs and adult cicadas up close. We took a lot of pictures and examined a number of specimens. She compared the molting process of the cicada to that of the painted lady caterpillars we recently studied. My daughter isn't afraid of the cicadas anymore, but she still doesn't particularly like them.

I do have one small, slightly disturbing footnote to add to this story. While running around the yard taking pictures of cicadas, I happened to notice a small structure attached to my back door.  It looks like the wasp war has begun again. Time to stock up on Raid anti-wasp spray.

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