A fairly representative New York City tree pit. “Pit” is definitely the word here. The hard-pan — calling this sterile-looking misery “soil” would be an insult — looks like something you’d find in a draught-ravaged desert. And you can imagine the gallons of poisonous dog piss that have been poured in over the years. It’s amazing that anything can manage to live in such grim conditions, but this London Plane tree (thought by some to be a spawn of the Industrial Revolution) manages, and so can whatever that is growing on the street-side.
My attention was initially drawn to this by the beast itself. A one and half inch long Cicada-killer wasp. When completed, there will be a tunnel from 30-70″ long, running 12-15″ below the surface. There are an average of 15 cavities off these tunnels, each containing 1-3 paralyzed cicadas and a single wasp egg. The eggs hatch in about three days, and the larva munches on cicada meat for about ten days, then it spins a cocoon and over-winters.
I’ve seen a lot of these big wasps in Prospect Park recently. (Although fearsome-looking, they are harmless to us lumbering mammals.) But I haven’t heard a lot of cicadas so far. This has been a bumper year for a lot of lifeforms, but this doesn’t seem to be the case for cicadas. Of course, August may see a lot more emerge, but time’s pressing, ye bugs! And there is much to be done! Annual, or dog day, cicadas emerge every year, as their name suggests, but each year’s cohort, or brood, has spent several years growing underground in their nymph stage. Last year was a good year for cicadas. Coincidentally, the wasps probably ate well. With their yearly cycle, it makes sense there should be a lot of wasps now. But now they have to make do with a the generation of cicadas from some time back (2-5 and 3-7 years are the numbers I run into on-line), which may not have been a boom year.A day later, in the rain.Third day of observation. Stain on bluestone not caused by wasp. So several feet of 3/4″-diameter tunnel are obviously going to create some spoil: the pile grows. The grooved path is interesting. It happens I noticed another couple of burrows in a tree pit around the corner from this one, with similarly developing paths:I’d like to see the wasp in action, but I don’t want to hang around and call attention to myself and thus the wasp because I fear not everyone would be so observational. Exterminators do good business for themselves by massacring these wasps, especially when they congregate as they sometimes do when the location is right.