Friday, August 16, 2013

A duel in the (front yard) jungle

This is what my thermometer said when we got up on the morning of August 15th here in Jonesboro, Arkansas. Early in the year I predicted that after a wet spring we would fall into an endless drought and searing heat. It seemed at the time like an easy prediction to make. Perhaps the only prediction we can make anymore is that we can't make any predictions.

As for the duel of my title: We also woke up one morning to find this on a pillar of our front porch.

Sometime the day before something had happened that left this rather grisly evidence behind.   A dead two-and-a-half inch long subadult Chinese Mantis was hanging there, its legs tangled up in the deserted web of a funnelweb spider. The mantis was holding some smaller creature in its spiny grip. Instead of its usual grass-green color, the mantis was a sort of oily black. The creature it was holding seemed to be a jumping spider.

I disentangled the mantis from the web and as I took it down horrible black fluid gushed out of its mouth. Obviously sinister things must have been going on. I set the mantis and its prey down on a table so I could investigate. The prey was Phidippus audax, a very aggressive large jumping spider, a big-game hunter for its size, though of course far smaller than the mantis, which was itself a very fierce hunter. What in the world had happened?

It was like a crime scene in all those British detective thrillers Cheryl and I are addicted to: I had to use all my forensic skills to try to work it out.

First of all, I need to eliminate a suspect. The mantis was tangled in the web of a funnelweb spider. But the web was deserted. Besides, it was a small web, which would have had a rather small spider in it, which would have run in the other direction if something as big as that mantis had blundered into it.  So that spider could have had nothing to do with this.  So let us suppose the mantis walked up or down the pillar. The smooth vinyl surface would have very few places for the mantis to cling to with the claws on its two pairs of walking legs (the forelegs are reserved for grasping prey), and it would have been crawling awkwardly, perhaps with a bit of slipping and sliding. Since there are numbers of these little funnel webs on the house siding it would not be surprising if the mantis got its legs tangled in one, and found itself hanging head downward. It would have broken out of it eventually, but while it was struggling it may have attracted the eyes of one of the many Phidippus audax jumping spiders that patrol up and down the porch. Here is what one looks like before it is impaled overnight on the forelegs of a mantis, and has sticky liquid spilled all over it.

If it saw something even as big as the mantis struggling and looking like it was in trouble, it would come over and investigate. Jumping spiders are very cat-like. They stalk their prey, and when they get a few inches from it, they make a cat-like leap, catch their prey towards the front of the body, and deliver a venomous bite.  I suspect the spider would have spent some time estimating the size of the mantis, and carefully triangulating the distance of the leap. What it would not have figured on was the mantis's ability, even after it was fatally bitten, to twist the forepart of its body around and in a flash grab the spider with its muscular forelegs and squeeze it in its powerful grip with all the nail-like spines pointing inward. There would be the spider impaled on the spines, there would be the mantis quickly dead from the fast-acting venom, but also, from the digestive enzymes injected in with the venom, with its insides turning to liquid, so that, in the normal course, the spider could suck out the substance. The liquid turning black would show through the mantises translucent skin, so that the normally green mantis would look black, and the black fluid would gush out the mouth when I picked the mantis up the next day.

All conjecture, of course. Perhaps the mantis wasn't struggling in a web at all. Perhaps the daring spider merely saw it and attacked and bit it, and the mantis turned and grasped it defensively, and they both fell off some higher point on the pillar and landed in the web down below. Phidippus audax (the 'audacious' jumping spider, its name means) is so aggressive that that would be just like it, biting off more than it could chew (one charged me once, when I annoyed it).

Okay, it's why I like jumping spiders so much. I've always liked them, and kept them for pets since I was a little kid. And I kept black widows and tarantulas and scorpions and snakes. Biting and stinging things, mass murderers, yes! The rest were boring grazing animals. I had a very tolerant mother, one neutral sister, and one phobic sister who was never allowed to find out.

1 comment:

  1. Your interpretation makes sense to me. Interesting as always!