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.

Thursday, August 8, 2013

More nice butterflies

In an earlier post I wrote about chasing after some attractive butterflies in early summer: The Olympia Marble, the Frosted Elfin, the Silvery Blue, and the Great Purple Hairstreak. Three of these have in common being in the group of butterflies known as the Gossamer-wings (family Lycaenidae). The other butterfly groups are more familiar to most people, the big swallowtails, and the whites and sulphurs flying over open fields, and the "regular" butterflies, the painted ladies, the buckeyes, the monarchs, the red-spotted purples.

Least familiar (and therefore most special) are the Lycaenids, which, I have written in another context, are to butterfliers what warblers are to birdwatchers. They are small, fast moving, often brightly or intricately patterned, sometimes appearing in great numbers, often very rare, always appearing unpredictably, always a pleasure to see, even the commonest ones. These are the harvesters, the coppers, the hairstreaks, the elfins, the blues.

Of the four species I wrote about in the earlier post, the marble is a white, but the other three were Lycaenids. Of the four special butterflies we have run into just now in mid summer, once again three are Lycaenids.

The first is not a great rarity, but it is so beautiful we are always grateful to see it. Some years there are a lot around, but some years they can be very scarce. This is the Juniper Hairstreak. A week or so ago we were walking along a dirt road at the Harold Alexander WMA, a road where we had often found special insects in the past. We were looking for tiger beetles, robber flies, grasshoppers, and of course butterflies. Recent rains had moistened the dirt of the road, which always brings dissolved salts to the surface, and freshly emerged male butterflies in their brightest colors were coming down to drink the salts, which they require to get into breeding condition. Cheryl spotted the tiny beautiful green butterfly (not much more than an inch wingspread) mud-puddling so intently it paid no attention to us at all. We could photograph it all we wanted, but, because it was at an awkward angle for us flat on the ground of the road, Cheryl enticed it up on her hand, to drink the salts on her skin.

A day later, taking advantage of the relatively cool settled weather, we were at Big Lake. A couple of weeks before we had been there and seen a few Bronze Coppers that looked like they could have been freshly emerged (the technical term is eclosed) from the chrysalis that day. Bronze Coppers are not only beautiful, they are also, in Arkansas, rare. Some years ago we found them at Wapanocca NWR, and then here at the Moist Soils Unit at Big Lake. So far as anyone knows, these are the only two sites where this species can be found in the state. It seems to be diminishing at Wapanocca, but it is getting commoner at Big Lake. When we found them here this year, we sent out the word, and a number of people had been here to photograph them. Now we were back checking on them, and they were everywhere, and we could not resist taking more pictures ourselves. The best thing was, the females were egg-laying on the water dock, their caterpillar host plant, which is common along the edge of the dirt path around the unit.

This was followed by a bit of serendipity, which it always is when you find a Harvester. You don't look for a Harvester, they just magically appear. This little Lycaenid has a subtle and quite handsome pattern and is noteworthy because it has carnivorous caterpillars. The female Harvester looks for some plant with an infestation of aphids and lays her egg on that plant, and the caterpillar goes off looking for the aphids to devour. But on this day it wasn't a female we found, it was a male who had set up a territory and was waiting for a female to come by (maybe they have as hard a time finding them as we do). The male carves out a territory of about ten feet along a path. He flies up and down the path slowly, showing off his tasteful pattern, and then he lands on a bush at about eye height looking around eagerly. Here he is on his bush.

Well, we don't have a Lycaenid for our fourth species; it barely counts as a butterfly. It is a Silver-spotted Skipper. And indeed we didn't even find the adult skipper, we found its caterpillar. The Silver-spotted Skipper itself is a nice enough creature which flashes a big silver spot on its underwing when it flies, but way too common to rate as being special. But you don't see the caterpillar every day, and get a chance to interact with it.

Cheryl found a rolled up pea leaf and unrolled it, and there was the caterpillar inside, immediately identifiable by its dark head capsule with the huge yellow fake eyes on it, to make it look like something dangerous to any bird that peaked inside the leaf roll. We had exposed it, so it went into its next defensive act, which was to open its jaws as wide as possible and try its best to look like the furious fiend from hell. We were impressed and rolled him back up.