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Mantisfly and Wolf Spider-A Terrible Tango

Thursday, August 18, 2011

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 for helping me narrow down the choices of mantisfly. And for helping me tell a fishing spider from a wolf spider!


I love that picture of the mama wolf spider with the babies on her back! I am a loyal fan of spiders, although I am not above gasping and leaping backwards if I come across a big one unexpectedly. I learned from FC a couple of years ago that you can see the wolf spiders' green eyes glowing if you look in your yard with a flashlight at night. I go out and look for them now and then in FC's honor:)

Very nice post, what a blog should be. I learned a lot, and love your pic and your compassion for creation.

Back before I was a better person, I once crushed a spider carrying babies. Not sure if it was a wolf spider, but it was HUGE and the babies made her look even larger. I didn't know until after the fact that what made her so large were babies as what seemed like hundreds scattered. :( That's my confession for the day. Sorry to the mamma I smooshed and the babies I orphaned.

Posted by Michelle from Ohio August 18, 2011 at 6:59 AM

Great post! I learned a lot today. I always wondered who ate the wolf spider ,since it is a large and tender morsel I'm sure.

The evolutionary paths of insects are endlessly fascinating. Wolf spiders are one of two types of spiders up here, and we often find them dragging around their egg sacks, or babies as they are very common on the tundra.

No mantisflies though, mores the pity.

I came across a fishing spider (my first, I think) this spring.
As it is with so many things, I'm seeing them everywhere-- NOW.
Mine, like yours, are nowhere near the water. They just cruise the bark of my trees in the backyard at night.
And they're HUGE--enough to give even me a small case of the willies.
Now a mantisfly would be a real treat. I've only heard the name--never seen the beast or known anything of their habits.
Thanks for tying all this together!

Oh, how apropos to my day! Just this morning I relocated a large black and tan spider (about 1 1/2" in diameter) that I found inside my kitchen cabinet. We're back for a week in our house in Central Mexico, and I thought maybe it was a scorpion. I just saw quick movement when I moved something next to it. Removing a few things revealed this really cool scared spider that only wanted to get away from me. She even flattened herself longwise into the fare crevis of the cabinet. ("You can't see me now.") She wasn't a wolf, and definitely not a Widow. Not sure exactly what she was but such a pretty thing. BTW, I love and also

Very interesting post. That momma wolf spider reminded me of a very special meeting with a momma spider. She had climbed to the very tip of some tall (chest-high) grass and her babies were parachuting off into the wind. I was on a field trip with my master naturalist class and we all were awed.

Sorry to be the only big baby to post a comment, but....


I love all flora and fauna... except big spiders! I just can't! The smaller ones are okay, but these guys are soooo scary to me!

Perhaps Chet Baker will protect me?

is that baby spiders? oh my how much are they? so plenty

Wow! I've always had a fear of spiders, but I have to admit that the picture of the spider carrying her babies was (almost!) heartwarming! Love your blog, Julie!

I can identify with the "Fear Factor" moment with the wolf spider you've pictured here. I'm a great lover of all animals, insects, etc. and when I saw this really big, plump spider on my patio I got really, really close with my camera on macro setting to take a photo only to take a look at my digital screen afterwards and notice all of the hundred or so wee babies she was carrying around. I did get a chill after being about 6" from her not realizing what those "bumps" were! Ah well. Thanks for bringing us these interesting tidbits about all species on your blog - now I don't feel so weird for constantly being on the lookout for new and fantastic creatures in my backyard and surrounds!

The photos of this wolf spider are amazing! Yet, kinda creepy because I'm afraid of spiders. Though, I love learning and reading about them. Here's one of my favorite sites about them (hope you'll like this too):

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