Wednesday, July 2, 2008

Meet Today's Special Guest

We have a nice wooded area directly behind our back deck. Late in the summer there are so many cicadas singing in those woods that it sounds like an impenetrable jungle at night. If I put a sound file up here you would be in complete awe. Not in awe of what you would hear, which just sounds like the soundtrack from a night scene in an old Tarzan movie, but rather in awe that I knew how to put up a sound file. Of course, I don't. But I do know how to put up a picture, and the one you see above is NOT a cicada.
I better explain. The picture above is of Sphecius speciosus (Drury), the cicada killer wasp. There are various types of cicada killers, but in our corner of the globe, ours are like this one. The males are smaller than the females but both are BIG. I mean, BIG. These are wasps that are between an inch and a half and two inches long. Since they look a lot like the wasps that fly around trying to sting humans for sport, the first time you see them you say, "Holy crap! That thing is huge." And then you run into the house--- quickly.
In July 2006 I first encountered a few of them in the yard and just thought they were normal, albeit very big, wasps. But last summer we had dozens of them so I decided I better figure out what they are and if they could kill an adult male human in his 50's with one swift sting. They are not dangerous to humans. Whew. They hatch out in July (around here-- your mileage may vary) and the males basically have two roles: 1) mate, 2) die. The females, having mated, look for cicadas. They find them on the trunks and lower branches of trees like the ones in our woods. They sting the cicadas. Then they hold the stunned cicadas with their legs and try to fly back to their burrow. They tend to fall to the ground a lot. So they drag the cicadas a bit, fly up to something higher, and launch themselves again towards the home burrow. It is a huge struggle and no doubt the female cicada killer wasp, somewhere along the way, becomes quite envious of her dearly departed mate. Once the gals get the cicada to the burrow, which is about 6 inches underground and about 10-12 inches long, they put it in the back of the home and lay an egg on it. Pretty soon they are dead too. That's the last we see of cicada killer wasps until the next July when the new ones feed on the dead cicada, dig their way out of the ground and do it all over again.
We don't want to kill all of these insects since they do keep the foliage-eating cicadas in check. However, we can't let them take over the front yard. Currently they only have burrows in a raised flower and tree bed. So far a half dozen burrows are in evidence, but it's early. Last year there were at least two dozen in that same bed. Last September I dug up the bed a bit and mulched it heavily trying to suppress them somewhat. I'll know in a couple weeks if it was successful. Meanwhile, I'll keep repeating, they won't sting you, they won't sting you, they won't sting you....
A good report about these odd creatures is found at Critter Zone.
Texas A&M University supplied our picture.