Ant Mimic Jumping Spider Myrmarachne formicaria

“Look at that ant,” she said.

It’s not an ant, though.

Ants have six legs, not eight.

And ants sure don’t have those iridescent chelicerae in front. Or the row of eyes right above the chelicerae.

It’s a jumping spider, apparently Myrmarachne formicaria. Look how the spider even holds its palps under the chelicerae to help with the disguise.

This is one of four males found overwintering in an old toy bulldozer left in the woods of upstate New York. We brought the toy inside and a day or so later noticed these. Once they had warmed up, they were quite active and readily accepted small flies.

Myrmarachne formicaria is a ant-mimic jumping spider that was first found in the United States (in Ohio) in 2001. Obviously its range is spreading.

Have you ever been fooled momentarily by a spider that was an ant mimic? Have you ever seen one of these?

Reference:

Richard A. Bradley, Bruce Cutler, Maggie Hodge. 2006. The first records of Myrmarachne formicaria (Aranae, Salticidae) in the Americas. Journal of Arachnology. 34(2):483-484.

108 Replies to “Ant Mimic Jumping Spider Myrmarachne formicaria”

  1. I’m finding a ton in my house now, they’re really cool but their presence worries me a bit(I’m a little arachnophobic, despite understanding that Most spiders are helpful and harmless) They’re interesting though I didn’t know they’ve been in Toronto for this long.

  2. I’ve been killing these in the house for the past month (August 2020) – thinking they were ants until I found one hanging by a thread. I’m in Euclid, Ohio, and Ohio seems well represented on this thread (no pun intended). Euclid is in Cuyahoga County which I have seen mentioned but, as fate has it, I work in Warren, Trumbull County which has been mentioned a few times.

    It is interesting that they were first identified in 2001 in Ohio. I have to wonder whence they came.

  3. I may have one in my backyard living in the roof overhang. It was raining and the little thing came down on a thread. I thought a 3 segment body on a spider was odd, so i googled it. I’m in Dayton Ohio.

  4. Bend Oregon. Have one jumping and dangling from my Adirondack chair. Looks exactly like the fire ants we have. Very arid high desert at 3500 feet elevation.

  5. I first noticed them in mid August 2021 In the kitchen, and bathroom. Then in the un-attached garage. Thought they were some sort of ant until I snapped a picture and looked close. They are quick little buggers! Town of Aurelius, Cayuga County NY.

  6. I have found two males in my back room since this Spring, it is now going into Fall. Thought it was an ant at first, until further study. I’m in Conneaut, Ohio.

  7. I’ve been seeing them for a few years. Mostly out side on my doors. But every so often I find one in my sewing room in the back of the house. They are aggressive when startled or threatened by another.
    I’m in Grand River, Ohio

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