Ant identification: August 2011 Archives

Hi there,

Writing from Caracas Venezuela to ask what huge ant this one might be. I'm guessing it was between 2.5 - 3 cm long (an inch long or slightly larger), but it's hard to say. I will go back and take more pictures of that hydrant's top nut again, with a ruler next to it, to be able to better estimate how long the ant might have been. Will post that pic also in this album on Picasa no later than this weekend:

It is easily the largest ant I've ever seen in my life. Friends on Facebook are saying it looks more like a wingless wasp than an ant, and I sort of agree. In any case, it was the size of a wasp, and looked really mean, even though it was moving pretty slowly.

Searched for "Largest ants" on Google and came across "Bullet ants," which made me worry whether those can be found in the Jardín Botanic of Caracas, and whether I had placed my hands so near such a dangerous little creature. But the photos I saw didn't look that much like a match, specially the jaws. Then found the "trap jaw ants", and those look much more similar, but apparently those are much smaller, not this big. So not sure at all what I came across.

Your help is appreciated. Great website by the way!

All the best,

Dear Raúl,

What great pictures! You're absolutely right: this is a "trap jaw ant," which in this case belongs to the genus Odontomachus. The one you saw is a little bigger than average because she is a newly mated queen who has just lost her wings (you can tell by the enlarged thoracic segments where her wings would have attached). She is looking for a place to start a new colony.

As you probably noticed, Paraponera clavata, the "bullet ant" has much differently shaped jaws (or mandibles). Believe it or not, they are also bigger than the ant you saw. They tend to prefer more densely-canopied forests. I would be surprised to see one on a fire hydrant, but you definitely have them in Venezuela, so it's good to stay on the lookout.

Even thought it isn't a real "bullet ant," you should still watch out: all Odontomachus have painful stings.

I can't tell what species of Odontomachus yours is, but the most common one in your area is Odontomachus bauri. Odontomachus chelifer is larger, but less common. There are many other species of Odontomachus in your region, though, and without looking at it under the microscope, though, I can't be sure.

I hope this helps!
Jesse Czekanski-Moir & the AntAsk Team

Hello from Mesa, AZ!!

Sooo... We moved into this house this past June and was horrified to see such large (large by this mid-westerners standards) ants, in very, very large numbers on our back patio one morning. That's when the war was waged. I love planet earth, and I respect the Eco system but I have a fearless 2 year old, which kind of changes my perspective on what I will allow in the backyard.

A little bit about our backyard guests. They don't like the heat. They are most active at dusk and dawn. They spread around their colony hole then have deliberate lines to food sources. Basically, they act like every other ant I've ever encountered. However, they have a very strong exoskelaton, and need to be repeatedly stepped on before being crushed. Apparently, the lizards in our yard.don't eat them, since they have such large numbers.

To date we've had an exterminator spray multiple times, landscaper used fire ant pellets, and this evening, out of frustration, I took a pick axe, lighter fluid, newspaper and a lighter to the colony. I wasn't sure if they stung before lighting them on fire, and quickly learned that they do sting/bite and.... it really hurts; which is upsetting because I don't want my curious toddler to have to endure this pain.

So... As I iced my ankle, while watching SpongeBob, and supressed the helpless feeling in the pit of my stomach, I found your site. And how WONDERFUL of a site it is!! After combing through it, I couldn't find my critters. So, here is my plea. What are these large black ants and how do I get them to move to my neighbors yard (or, how do I kill them?). My apologies for not having better pictures, it was the best I could do.

Best Regards,


Dear Jacquelin,

We are sorry to hear you are having a problem with the ants in your yard. Moving from the midwest to the deserts of Arizona means you will have to adjust to your new neighbors and this includes the ants. On a positive note, many of those new neighbors (including the ants) are really amazing! In fact, Arizona has over 300 species of ants. Antweb has a page dedicated to the ants of Arizona:

The ants you have in your yard are harvester ants in the genus Pogonomyrmex (probably Pogonomyrmex rugosus). These ants are primary seed harvesters, although they will also collect dead insects and other foods. You can read more about this species and see photos here. You can also find distribution maps for the North American species of Pogonomyrmex here.

Although these ants do have a painful sting when disturbed they are not likely to enter your home. I know that you are concerned about your child, but I would talk to other parents in the area to see how they have learned to live with these ants. Harvester ants are a common and important part of the desert ecosystem, so trying to find a way to coexist with them will be easier in the long run than trying to get rid of them. If you are determined to get rid of the harvester ants in your yard read here and here.

I hope you find a way to enjoy these beautiful ants (see close up photo here)!

Best regards,
Corrie Moreau & the AntAsk Team

I recently traveled to Florida, I observed these ants. Could you please tell me which species are they?

Thanks for your time, Greetings




Dear Annie & Jose,

The ants you found are likely the following:

Photo 1 (reddish ants on sand): Dorymyrmex bureni
Photo 2 (black ants): Paratrechina longicornis
Photo 3 (black ants attaching large ant): Paratrechina longicornis attaching Camponotus floridanus

If you are interested in the ants of Florida, the following websites may helpful:

Best of luck,
Corrie Moreau & the AntAsk Team

We live in Puerto Rico, where ants are varied, plentiful, painful (lots of fire ants...) and often like to move into our (concrete block) house.

We've been having frequent infestations of these little (2mm or so) ants. At first I thought they were pharaoh ants but now I'm thinking the coloration is wrong (these guys have light colored abdomens and dark heads, not the other way around). We have been trying to get rid of them using Maxforce and more recently Advion. They swarm the bait and then wander around like they are dazed and confused, sometimes seem to dwindle a bit but they don't die out. They seem to like to make nests in small openings in our walls (e.g., breaks in the grout lines but they also like our kitchen cabinets (but don't seem to bother getting into the food, just collect crumbs etc.) and have even once moved into our clothing chest of drawers (we don't notice their new trail quickly enough).

Seems I need to know exactly what they are to get rid of 'em effectively so would very much appreciate your thoughts.


Dear Miri,

We are sorry to hear you are having problems with ants in your home. The ants you are finding are the ghost ant, Tapinoma melanocephalum. This species is a pest in many places in the world.

You can read more about this species of ant here, here, and here.

In addition, you may try some of our suggestions for other pest ants in homes from this previous post here.

Best regards,
Corrie Moreau & the AntAsk Team

Hi Antweb Team,

I am Dai, in Viet Nam. These are some pictures of Polyrhachis species that I found in a wet land, Sai Gon outskirts.

I kept them for a while. They ate only sweet things like sugar, watermellon... I did put some fish pellet but they took and threw away from the nest.

They also use larva to "weave" like P. dives but I am not sure it is. I am not specialist, maybe other species in the genus also do "weave"...

From these pictures, could you please tell me what species it could be?

Many thanks
Dear Dai,

Thank you for contacting AntBlog! We have asked an expert on Polyrhachis ants, Rudy Kohout, from the Queensland Museum, Australia to help with the identification. Here is what Rudy had to say:

"The photographs do not show all the characters necessary to identify them, but it is clear that the specimen represents a member of the Polyrhachis dives species-group and most likely P. dives itself. This is a very widespread species, ranging from south-east Asia (including Vietnam) south to northern Australia."DSC06148.jpg

Many species of arboreal Polyrhachis use their larvae to weave or sew leaves together to build their nests, much like Oecophylla ants.

Good luck with your spiny ants!
Rudy Kohout (guest expert), Corrie Moreau & the AntAsk Team


I live in mid west Indiana I found this ant queen under a rock. I found her in my yard in town under a rock behind my house. There is an old oak tree in my neighbor yard but I examined the tree and found no ants. However, oaks are common in the town. I live in a small town 20 min south of Terre haute Indiana, near the Wabash river so not far from Illinois. Can you tell me what species she belongs to? I think she may be of the genus Camponotus. I have included pictures. She has already started to lay eggs.


camponotus castanaeus.jpg

Camponotus castaneus dealate queen

Hi Kris,

We have deferred your question to James Trager, who has been of invaluable help with ant identifications for this blog. He thinks this is Camponotus castaneus, so you were correct with your assumption that it belongs to the genus Camponotus. James is Antweb's curator for Illinois and Missouri. In his experience, this ant species "is a denizen of upland forests, with a variety of dominant tree species, almost always with lots of oaks." Thanks very much for providing such detailed macrohabitat information.

Thanks for your question,
James Trager (guest expert), Steffi Kautz and the AntAsk Team


My name is Jeremy and I live in Saskatchewan. A few weeks back we found an ant, like the one in the picture, throwing sawdust-like material by our backdoor entrance in our kitchen area. I ripped the nearest board up off our outdoor deck (this turned out to be unnecessary), sprayed some kind of powdery anti-ant stuff outside the door and I caulked all possible entries into the house. The powder washed away with rain and the caulking was of little use because the ant just burrowed right through it. Then we called an exterminator. He came out and couldn't identify the ant on sight. The exterminator went back to his office with the ant, called us back and said it isn't a carpenter ant.

I sprayed the powder again and we bleached our floors. Over the next 2 weeks, we saw no sign of ant activity and we breathed a collective sigh of relief.

However, the past 2 days, the ant has returned and he brought his friends. Two nights ago, we found and killed 2 or 3 ants. Yesterday, during the day, about 4 or 5 ants. Then last night, probably about 15-20 ants. I killed 1 or 2 soldiers who were markedly larger than more common guys (the more common guys are in the picture).

In response, we pulled out the appliances, cleaned and bleached behind the floors, bleached the entire floor to hopefully rid any phermone trails, since the caulking was previously useless, I put petroleum jelly in the spots on the base-board and at the door entrance where these ants appeared to be emerging from the wall. I read somewhere that this stuff will dissuade ants.

So my question, is this indeed a Carpenter Ant? I don't want to spend another $75 to have a guy come out and tell me that it's not a carpenter ant.

carpenter ant.jpg

Carpenter ant in home.

Hi Jeremy,

Thanks for contacting us! We have contacted ant expert James Trager, who regularly helps us out with ant identifications. Here is what he had to say:

"It is a carpenter ant ... and that exterminator was in error.

Even though the pictures are a bit fuzzy, the structure of the dorsal mesosoma is visible and corresponds perfectly to that of many Camponotus. The red meosoma and the black head and gaster indicate C. novaeboracensis, a common carpenter ant across southern Canada. Another possibility is C. vicinus, but it is far less likely to excavate rotten wood. In Jeremy's case, I suspect he needs a carpenter to replace dry-rotted wood more than he needs an (incompetent) exterminator. Pulling out the infested wood would kill both birds with one stone, if you will."

Here is a bit more info on carpenter ants and for some general advice on how to get rid of ants in your house, check out this post here.

All the best,
James Trager (guest expert), Steffi Kautz & the AntAsk Team


We live in the northeast corner of Vermont - close to the 45th parallel. My husband was logging dead trees just inside the woods. He cut down a two-part cottonwood that was large. It was like two cottonwoods had grown together or one had been cut long ago and shoots grew up onto the old tree. But where the V of this tree was, there was soil and that is where the ants lived. When the tree fell, the ants began moving the pupae into the forest floor. Right down under the earth. I did the best I could with the photos and have collected them into a Flickr set. Could you please ID them, if possible? The photos were taken on July 9, 2011.

Thank you very much for any help,
Barton, VT


Lasius umbratus with pupae in rotten log.

Hi Andree,

Thanks for your question. We have deferred to James Trager, an ant expert with a lot of experience in ant identifications and a expert naturalist in general. Here is what he had to say:

"Almost certainly Lasius umbratus. This speices is not arboreal, but lives in soil, logs, stumps, or dead hollows of trees. It lines its nest chambers with a mix of wood pulp and a characteristic black fungus, visible in the pictures. They cultivate large numbers of pale reddish tan aphids on roots, probably including those of the tree in which they lived. In winter, the aphids are gathered up and pass the cold period in a large chamber together with the ants, then in spring are dispersed out among the roots to feed. The aphids provide lots of honey dew and some meat."

So, you not only found ants, but an entire little ecosystem when cutting the wood. Very interesting!

All the best,
James Trager (guest expert), Steffi Kautz & the AntAsk Team

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