Thursday, August 18, 2011

Mantisfly and Wolf Spider-A Terrible Tango


Mantisfly - Dicromantispa sayi

Another treasure of the garden--a mantisfly. These little gems are not terribly common, and I'm glad to find one every few years. I found this one floundering in my little water garden and saved it by putting it on some petunias to dry out. Predatory, as its spined and grasping front legs would suggest, the mantisfly is a neuropteran, related to the predatory lacewings, and like them it flies reluctantly and weakly. Actually, it prefers to wait around on flowers for something to blunder by to be grabbed and eaten. Me too. But usually I wind up cooking instead.


Such a charming bug--tiny but outfitted with everything it needs to grab smaller insects, process and consume them. I'm amazed at the convergent evolution that gives this insect the same bug-eyed countenance and miraculous forelimbs of the big praying mantis. Just a real good preying apparatus, and it works for both mantids and the unrelated mantisflies.

 

There, the similarities end. And the story gets weirder, as it usually does with insects.   Larval mantisflies, which are speedy and flattened and look something like beetle larvae, parasitize spiders and their eggs. They hitch a ride on a female spider, like a wolf spider, and get into the egg sac while it's under construction. They suck the eggs dry with tubular mouthparts, then pupate in the nice strong silk egg sac. When they pupate, the adult emerges by chewing its way out of the egg sac. Wow.

Dicromantispa sayi, one of six North American species in its subfamily Mantispinae, has a wide range, from southern Ontario west to SD, Utah, NE and AZ, and south to FL, Mexico and Panama, the Bahamas and Cuba.Worldwide, there are about 400 species of mantisfly. Think about that for a moment. It's a little crazy when you think about it, and compare insect diversity to, say, mammalian or avian diversity. That's like saying there are 400 species of oh, say, gnatcatcher worldwide.

So when you see a big scary spider, know that there's something much scarier haunting it, and cut it a break. This, according to Eric Eaton of BugEric on Blogspot, is a fishing spider, genus Dolomedes, family Pisauridae. What it's doing on a dry ridge with two nearly-dry, fishless streams on either side is anybody's guess. Headed for my goldfish pond, hoping to snag a half-pound snack?

                             
I posted the photo above thinking I had a wolf spider. Below is a real wolf spider. And this is the one I hope you'll cut some slack. Because if the wolf spider had been able to hatch all its eggs in its carefully tended silken sac, which the female spider hauls around beneath her abdomen, you'd have seen something like this:


which we at first thought was a very fluffy wolf spider but which, upon closer inspection, resolved into THIS
 which I'm sure many people consider a Fear Factor moment, being covered in your own squirmy seething chillun'. I found it charming. So as much as I love finding mantisflies around, I'm thankful on the wolf spiders' behalf that there aren't a lot more of them.

Thanks to my friend Eric Eaton and the folks at Bugguide.net for helping me narrow down the choices of mantisfly. And for helping me tell a fishing spider from a wolf spider!


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