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.

105 Replies to “Ant Mimic Jumping Spider Myrmarachne formicaria”

  1. I’ve been fooled more than momentarily by ant mimic spiders. Some species are downright unbelievable!

    You’ve captured some nice shots of this one, Roberta- I love those chelicerae!

  2. Cool, I just saw and photographed one of these today. For a moment, I thought it was Formica pallidefulva!

  3. I just found one of these guys in Ithaca. Pretty impressive spread from ohio

  4. Just saw my first one today in my job trailer in New Lyme, Ohio. Knew it was not an ant but couldn’t nail down the type of spider. Your photo sealed it for me I was just getting ready to post my photo of it for help.

  5. I’m in Ithaca too and just caught one of these in my office. I saw it walking on the wall near my calendar a few days ago and thought it was just an ant…saw it again today, noticed the 8 legs and became intrigued. After catching it I googled it and here I am…kinda crazy that other Ithacans beat me to the punch…

  6. Just found one of these in the house for the first time…located a little west of Rochester NY. Never seen one before, inside or outside. Neat little things…

  7. I live in erie pa.and I definitly have these spiders in and around my house! I caught a few and brought them to our local exterminating business and they had never seen them! Im trying to find out if they bite humans orour pets because I am finding an alarming amount of them IN my house !!!! Do you know to get rid of them? How fast do they multiply? Do they live in colonies like ants? Are they poisonous?any information would be great ! Thanks!

  8. Carla,

    You have a sharp eye to realize that they were spiders and not ants.

    There is no need to be alarmed. In most parts of the U.S., the only spiders you need to worry about are the black widows and the brown recluse. These are jumping spiders, not related at all.

    From my observations, the spiders overwinter as adults, and this time of year they would be looking for places to spend the winter. If they really bother you or are in high numbers, a vacuum cleaner would be your best bet. Just vacuum them up, and throw away the bag after you are done if you are really worried. Otherwise, you can slip a cup over them upside down, slide a paper under under the opening, and cart them back outside (away from the house).

    By the way, this advice is based on the facts you provided and is only for educational/informational purposes.

  9. These spiders certainly look like an ant. These Jumping spiders make up the family Salticidae. This is the biggest spider family, numbering about 5,000 species. If someone is interested to know more about these jumping spiders, he/she should visit jumpingspider.net

  10. We live in Barberton Ohio. We just watched this spider hang from the ceiling in our bathroom. It is is now taped to paper. Are these ants poisoness? I am 30wks pregnant and kind of curious

  11. I saw one last week in Akron,Ohio. Totally thought it was an ant until it shimmied down its web to the ground! I’ve never seen them either.

  12. Amanda,

    If you have any questions about what kind of ant it is, you might want to check with your local Cooperative Extension office. They would probably be listed under county government. Most offices have staff and volunteers to answer those kinds of questions.

  13. I am from the South Coast of New South Wales, Australia. Just found one of these spiders. I thought it was a very strange looking ant at first. Never seen a spider like this before, or even heard about it.

  14. I live in a suburb of Buffalo NY, and we have a ton of these in our office building!!! Quite interesting, but we cannot seem to get rid of them.

  15. I just found one of these on the door of my shed in Youngstown, Ohio. Very interesting, and quite active. Even reared up to challenge me when I took its picture.

  16. Just found one of these in the Garage. In Ripley NY. do they bite? and are they poisonous? can they harm animals?

  17. Well, now they exist in Troy, NY just outside of Albany. I was installing door trim a little while ago when this ant comes strolling by. I tried to knock him down with a putty knife and lo and behold he SPUN A LINE and eased himself to the floor. I couldn’t believe my eyes. I caught him, counted his legs and yup, he has 8 legs. incredible. I just had to google him and here I am. Just wanted to let the world know that these critters are moving fast, if they were only seen in Ohio for the first time in 2001.

  18. I found my 1st one at work today in Orchard Park, NY. I took some pics then free’d it outside. Good thing I found it, otherwise my coworkers would have killed it.

  19. At work in buffalo NY it is invested with them, no one will believe me that they are spiders.

  20. I just found one on my kitchen and was wondering what kind of spider it was. He keeps waving his two front legs in the air, as if he’s pretending they’re antennae instead.

  21. I had seen several of these in and around my house in Trumbull County, Ohio, thinking they were ants. Then one day I saw one lowering itself to the floor on a line of web and was baffled. I had no idea what it was. My husband thought I was crazy when I told him about it. I proved him wrong with the power of Google. Now when I see one, I just watch it. They are fascinating creatures, and the accuracy of the mimicry is unbelievable.

  22. How would the female look like? With short chelicerare? Like in the case of Myrmarachne plataleoides?

  23. I just found one or two in my apartment today in Youngstown OH. I had never seen ’em before and thought it was an ant, as upon first look, I only saw 6 legs and a huge pincers. I used a cup and paper and tossed it outside this afternoon. Now, I just found one (same one, idk) in another room. This time as I approached, he was rather aggressive. I thought it was weird for an ant but didn’t want him hanging around in case he discovered food and brought back his entire family. As I cupped him again against the wall, he fell from the topside to the bottom so gracefully with webbing. Aha! So not an ant after all! Did my search begrudgingly (I dislike bugs especially spiders…I still am getting the shivers) and found this site. Thank you for making it short and sweet and to the point for those of us who get creeped out easily. Although the pictures were hard to look at! LOL.

  24. They are now in Canada, Ontario Eh. These little guys are spreading like wild fire. I found mine hanging from a ceiling and wondered how a ant did that…. No doubt about it, it’s a jumping spider.

  25. I had just seen one last week, it looked like an ant from far away but when I looked closely I saw the eight legs and those fang looking things at the front so I knew it was an ant mimicing spider. Pretty cool.

  26. Just saw one at work, just north of Toronto, ON. Would have thought it an ant except it darted sideways.

  27. I just found one in my new pole barn in Hilton NY. Very cool little spider. Not sure how it will fare with the giant wolf spider that share’s the barn with me.

  28. Found one in an art studio in syracuse, NY, climbing up it’s web line to the slab roller. Was totally convinced it was an ant, those 2 front legs looked like antenna as it reared up and challenged me. I hope it scurries into another part of the building, yet super intriguing.

  29. Does anyone out there know why certain spiders have evolved to mimic ants? We have these in England and although I’ve never actually seen one I find them intriguing.

  30. Tom,

    It’s most like the spiders mimic ants because ants are well defended. Predators that avoid ants will also avoid the spiders.

  31. Just found one today in Gates, NY outside of Rochester. Thought it was an ant until my son noticed how many legs it had

  32. Just found one in my house in Niagara Falls, ON! I was like what is this creepy little thing it isn’t an ant!

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