Monday, July 9, 2012

Still stuck in the garden

But we're still finding stuff. Let's start with this wonderful shot Cheryl got of a jumping spider with the enormous horse fly it had just caught.

Only a while before that she had taken another terrific spider picture, this one an arachnophobe might think she had taken under great stress, except she's not afraid of spiders, and didn't think a thing about it. A trapdoor spider had come up above ground and was running across the yard. Cheryl tried to slow it down so she could take a picture of it. She put all kinds of obstacles in front of it, but it kept running, until she put her hand down to block it, and it climbed up on her hand and stood still, and she took the picture with the camera in her other hand. It was a wonderful rubbery looking spider that might have been a plastic one you buy for a Halloween prank.

A last note on spider developments in the yard: The dozens of baby Argiope Golden Garden Spiders have been working themselves up the ranks. I believe they sit patiently in their webs until they've made a couple of good kills, which fattens them up enough to molt into the next instar. Some that have never caught anything are still dots in postage-stamp size webs. But the females who cast their nets in the most favorable spots are now in their penultimate molt. With one more molt they will be fully adult and ready for mating. Here is one of the successful ones (although frankly her web looks like one of those 1950's experiments where they fed spiders LSD to see what would happen). She may not realize it yet, but she already has a tiny boyfriend waiting in the background to be the first one on the spot when her big moment comes.

To switch now from fierce predator to mild nectar sipper: Because of all the acre-feet of water we are pouring into our garden to keep it at least half alive, we seem to have a fix on the neighborhood's butterflies, with many recognizable individuals spending every day with us. For instance, early in the spring the duskywings, a kind of large dark skipper, were out in droves, with Juvenal's, Horace's, and Sleepy Duskywing common, and the much scarcer Wild Indigo Duskywing occasional. Well, the first three have long since faded away, and now we notice we have two or three Wild Indigos visiting our flowers every day. It's odd to have the sometime rarest species become the commonest. Here is one of them.

Duskywings are an acquired taste. The different species all look practically identical, and they can be really frustrating to try to sort out. Often it's a question of examining tiny white marks on their upper wings. Sleepy has no white spots, Wild Indigo has a few, Juvenal's and Horace's have a few more, but in a different configuration from each other. If you're interested, click on the link (above) to Robber Flies of Crowley's Ridge, scroll down to the bottom of the page on the left, and click on Spreadwing Skippers.

Swallowtails are easier to tell apart. I reported on an earlier blog that, to try to keep them safe, we brought in some of our Black Swallowtail caterpillars to raise in the house. They have all made chrysalises now. Those on brown stalks made brown chrysalises and those on green stalks green chrysalises (don't ask me how).

They aren't in the clear yet. It's possible that before we brought them in a short-tailed ichneumon (a kind of parasitic wasp) laid an egg inside them. In that species the larva waits until the caterpillar forms a chrysalis, and it then systematically devours it from the inside, and in the course of time instead of a swallowtail butterfly an orange wasp-like insect emerges from the chrysalis. It's always a bit disappointing, but on the other hand, without these natural controls, swallowtail butterflies could cover the earth several feet deep.

More positively, the Spicebush Swallowtails that visit our phlox every day are in courtship mode. Here is a picture of a male hot after a female, and in this picture you can learn how to sex them: the female has bright blue on her hind wings, the male a paler sort of gray-blue.

The more closely you observe insects, sometimes the more bizarre they become. They are shape-shifters, many devote amazing, even artistic, energy to looking like something else. Look at this wonderful praying mantis behaving like a blade of dried grass.

He has a double purpose to be invisible. One, he wants to avoid being seen by a bird that might eat him, and Two, he doesn't want to be seen by an unsuspecting small insect that might land within reach of his spiky arms. Now here's a red wasp that wants to be seen. Its bright color advertises its painful sting, which will discourage most predators from trying to make a meal out of it.

Okay, now what if you used the back half of that dangerous looking wasp, and then stuck the front half of a praying mantis on it, and maybe for good measure added Lucy-in-the-sky-with-diamonds eyes? You would get something like this.

This is a Mantispid, a member of the very weird order of insects called Neuroptera, which includes Dobsonflies, Ant Lions, and Aescalaphids, creatures often looking like they were put together from the spare parts of other insects. A Mantispid's life history is stranger than anything you could imagine. As tiny just-hatched larvae they wander around until they find a spider, and they quickly climb onboard. If it's a female spider, they stick with it. If it's a male, they ride on it until it mates with a female, at which point they climb onto the female. They then wait until the female makes a nest and lays its eggs in it, and they get inside the nest too. Without complicating things to much, I can mention here that Mantispids undergo "hyper-metamorphosis." They have at least two larval forms, first the active one that climbs onto the spider, and second, a fat blobby one that sits grossly in the middle of the nest gorging on eggs and spiderlings. They do this until pupahood, and finally hatch out of the nest as adult mantispids, sometimes to the astonishment of arachnologists who thought they had brought home a nest of spiders to study. I'm just covering broad details, which are weirder and weirder the more deeply you go into it.

We've kept Mantispids for pets. They're very comical things, some mimicking the red Polistes wasps, others the black and yellow bands of yellow jackets. With astonishing speed they can catch a mosquito or other small insect in their grasping legs. These aren't large things, so unless you are watching for them, you are apt to miss them altogether, which would be a shame. Cheryl recently found the tiniest one we've ever seen, and photographed it next to one of her fingers for scale (her hands are the measure of all things when we are photographing insects). Here it is.

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