There has been a lot of talk about cicadas lately, and they have finally started to come out. These are periodical cicadas that emerge on a 17 year cycle. The cicadas that are emerging this year are from brood X and last appeared in 1987. Since then they have been sitting underground, tapped into the roots of trees, slowly maturing. During the last few days the mature nymphs have started to emerge in this area. They climb a vertical surface: tree, lamp post, blade of grass, you name it, then molt, and you have a winged adult. The adults move up into the tree tops and begin wooing, which pretty much sounds like one of alien space ships from any of the old 1950's sci-fi movies.
For some reason there aren't any in my yard, but I took my kids to a park about a mile away yesterday and they were all over the place. The song is pretty cool and amazingly loud. Even though there aren't any in our yard I can hear them calling pretty clearly from the woods that surround our subdivision.
In any case, they come to mind here because it strikes me that they have taken the whole arribada thing to an extreme. Turtles that nest en masse probably do so as a mechanism to ensure that as many hatchlings survive as possible when they emerge, also en masse. Ideally predators become sated picking off the hatchlings that emerge early allowing more of the late ermergents to survive. And the cicadas do this on a 17-year cycle!
It makes me wonder how many other taxa, or what proportion, have adapted similar strategies to increase the survival of their young? Coral come to mind which spawn syncronously, as do many fish species, like grouper that have spawning aggregations.
Click on the image (couresy of J. Stein Carter from his website) or follow this link to learn more about cicadas.