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Hello, I am in Toronto and have located a colony of small reddish/brown ants living under the 6x6 wooden ties surrounding my lawn. My question is: are these ants beneficial to the eco-system and should therefore be simply left alone? I have a wooden porch: should I be concerned about 'an invasion'?
Secondly, I have occasionally seen the same type of ants moving in mass across sidewalks - thousands of them - so many that it looks like a brown stain on the sidewalk. Can you tell me what causes this phenomenon?
Thanks for your help,


Dear Mary,

Thanks for writing to the AntBlog! It was a pleasure to answer to your interesting questions.

Ants play a huge role in an ecosystem: they are diverse (we estimate 30,000 ant species living on Earth), and are in great numbers everywhere (all the ants weigh almost the same as the 7 billion human beings). Along their evolution, ants established ecological relationships with a large array of plants and animals. They are prey, predators, symbionts, parasites (there are even slave maker ant species!), seed dispersers, pollinators, and so on. Ants move more soil than earthworms. They impact and are impacted by almost everything surrounding them. More, they have a short lifespan, and that means their nest population is constantly being replace by new generations of ants. So, if something happens with an environment you will notice the effects faster and with more details if you look at the ants, and it will be much more effective than looking at birds or mammals, for example.

Just for curiosity, ants are important for other aspects of human societies. Their behavior is used as model to create smarter traffic lights, or to develop software that will evaluate the response of our bodies to the effect of new drugs (see here, here, and here). Anti-inflammatories, antibiotics, and even drugs to fight against cancer were/are being developed with substances ants secrete (here, here, here, here, and here). Finally, have you ever thought of including ants in your menu? Many human cultures around the world did! See here.

Salad of Oecophylla smaragdina queen brood mixed with some worker ants, mint leaves, spring onion, chili, and fish sauce. Popular in Thailand and Laos. Image by Joost Van Itterbeeck/

Based on the behavior you described, I believe you found pavement ants (genus Tetramorium). Unlike carpenter ants (genus Camponotus), pavement ants don't cause any structural damage to your house (and just to take Camponotus out of the fire, those ants nest in decayed wood; so, if the wood in your house is in a good shape, carpenter ants will not be a problem).

Pavement ants get their name because they nest usually underneath or at the edge of sidewalks, and other hard surfaces. They are an introduced species from Europe; and in your garden they will: harvest seeds -- some of which will eventually grow around their nests; tend insects on plants, collecting sugary dropping they produce (A.K.A honeydew), and protecting them from predators; and predate other insects.

The pavement ant workers are dark reddish-black, about 2.5-4 mm long; the petiole, which connects the mesosoma (i.e., the modified thorax of ants) and gaster (modified abdomen), has two segments. The posterior part of the mesosoma has two spines that project upward, and they have a stinger in the last abdominal segment.

Lateral view of Tetramorium caespitum. Image by Will Ericson/

When two pavement ant colonies overlap, worker ants leave the nest to establish their territory boundaries before ants from the other nest push them out of there. Then, ants coming from each nest collide in a massive battle. The combats are sometimes ritualized: they will just size each other strength, and produce very few casualties. In another occasions, they will ripe one another apart, and thousands of corpses will be left on the sidewalk afterwards.

Sidewalk ant war. Image by the fabulous Alex Wild (


Flavia Esteves and the AntAsk Team

Cohabiting ants

Hi there, loving your page!

I am on holiday in Andalucia, southern Spain, and right by our front door there is a colony of what look like harvester ants. No more than fifteen centimetres away there are some holes from which some very tiny red ants emerge, about a quarter of the size of the smallest harvester ants. Are these two separate colonies, or different types of the same ant? They don't look related and they don't appear to cross into each others territory. I would have thought they'd be fighting all the time if they're not related. Why might this be? Are their diets different enough that they aren't in competition? Sorry to bombard you with questions!

Kind regards,


Dear Ian,

Greetings from San Francisco, and thanks for writing! We contacted an expert on taxonomy and ecology of Europe and Macaronesia ant species, Dr. Xavier Espadaler; here is what he had to say:

"It is not an unusual situation for different ant species to have nest entrances rather close. Coexistence is a possibility; fighting is another possibility. But if the two societies are already nesting close to each other, it is likely that they differ in some way, in their daily activity cycles, or in their food habits.

It is possible that the harvesting ants (Messor) are living close to a Pheidole pallidula nest. This last species is all too common in AndalucĂ­a. Their nest, with one or a few entrances, is usually surrounded by the tiny remains of the scavenging they do upon any kind of arthropod remains or corpses; they may capture living prey as well, if small enough. The remains look like a dark zone, somewhat semicircular, bordering the nest entrance. If you are able to look at them under a magnifier, you would see shining heads, wing or leg or thorax fragments, that are the non edible parts of their foraging."

Hope this helps,

Xavier Espadaler, Flavia Esteves, & the AntAsk Team

We have a huge colony that has seems quite mature. Has been there for a long time. They are small black and red ants and they have a nasty little bite. Unfortunately we need to place a structure right over the ants colony. We do not want to harm the ants and would prefer to somehow move the colony.

It may a good time of year to do something with a deterrent, as they are very active. I thought we might be able to lift the whole colony, using some sort of bucket, during the night, so they are not away from the nest. I imagine this would cause havoc and might not succeed.

We live in Victoria, on Vancouver Island.
Any suggestions? Any input would be appreciated.



Good afternoon, Joan!

Interesting question! It sounds like you have a colony of the quite charsimatic Western thatch ant, Formica obscuripes, in your yard. Fortunately I have experience with this species, given that there is considerable variation in the construction of thatch nests among the species in North America. Unfortunately, it may not be possible to relocate the colony without destroying it. The above-ground thatch---while impressive in stature, especially in the Pacific Northwest---is not the primary housing-unit of the colony. The thatch is like a compost pile which is warmed internally by the decomposition of the organic material used to construct it. In this way the above-ground component of the nest functions like an incubator, where the ants will place their developing young during the late winter and early spring months, allowing the young ants to grow even when there is snow on the ground. Now, the problem is that the most important members of the colony---the queens---don't like to stay in the thatch part of the nest. The queens are usually encountered in underground chambers which may extend several feet beneath the thatch. Thus, in order to relocate the colony you would need exquisite timing so that way you may move the thatch with the queens in it. Perhaps the best time of day for this would be in the morning or late afternoon when it is cooler out as the queens may migrate up into the thatch (although this idea has not been tested).

If you were to attempt to move the thatch there would be no way to do it without upsetting the workers as they are very territorial and aggressive about their mounds, and there is no guarantee that even if a queen were in the nest that she would be able to successfully excavate a new nest once moved. However, if you wanted to go through with the move I would recommend bringing a few 5-gallon buckets, a shovel, gloves, and duct-tape. What you could do is tape the gloves over long sleeves and your socks over your pants (trust me on this one!), then take the shovel and transfer as much thatch and soil from beneath the mound as fast as possible into the buckets (which hopefully you have lids for). You could take these and dump them together in an area very similar to where the colony is now, presumably near some Douglas firs. You might not have to dig too far down into the ground, as I have found queens at the soil surface and just below---less than a foot. I'm pleased with how considerate you are about these colonies! They may live for over a decade and house several thousand busily working individuals, let alone the fact that this species is ecologically important in your region.

Good luck with the ants, and I hope I helped answer your question!
Brendon Boudinot & the Ant Ask Team


I'm sorry if it's bad form to send pictures of dead creatures, but this particular one was acting belligerently in my bed, forcing my hand. I think I crushed its thorax in the act.

I encountered this insect while living in the central part northern Namibia, maybe 10km south of the Angolan border. I have no idea what it is. I've always wanted to learn more about it, and when I discovered this blog I thought it might be a place where I could get some guidance.

Can you identify this? Is it even an ant?

Thanks a lot,


Thumbnail image for Thumbnail image for DSCN0730.JPG



No worries on bad form. Your inkling that this is not an ant was correct! This is a Solifugid, more commonly known as a sun spider, wind scorpion, or camel spider. Although it is an arachnid along with scorpions and spiders, most species of Solifugids do not have venom, and are not much danger to humans. The only thing you might want to watch out for is their powerful jaws, which they use to hunt ground-dwelling arthropods and other small animals.

Hope this helps!


Max Winston & the Ant Ask Team

Hello there,

I have a query about these ants we saw in our local park in Madrid, Spain. The ants themselves seemed fairly standard, with one nest hole, and a long line of foraging ants heading out to a nearby area and coming back with various tasty tidbits. As can be seen from the photo the ants were a number of different sizes.


However, amidst the ants were several white creatures (in the photo centre left, bottom right and the tail of one top left).


These looked nothing like ants, but appeared to be coexisting with them peaceably. They were going in and out of the ant hole, and were ignored by the ants. One or two travelled along the foraging line, but didn't appear to do any actual foraging. They were quite quick too, about as nimble as the ants.

Any information as to what these might be would be gratefully appreciated. My guesses would be a) some precursor ant stage (pupa or some such) b) other insect living symbiotically with the ant or c) I have no more ideas.

Many thanks!



Hi David,

Your second guess is correct! The other insects in your photograph are in fact silverfish, cohabiting with the harvester ant Messor barbarus. There are many species of such myrmecophilous (or "ant-loving") Zygentoma around the world, with 16 occurring in the Iberian Peninsula alone. Unfortunately, without a clearer image, it is difficult to provide you with a more precise ID (several different species have been observed in Messor nests in particular), but based on a superficial diagnosis, they most likely belong to the genus Neoasterolepisma.

Silverfish are among a wide variety of other arthropods (including beetles, crickets, spiders, millipedes, even cockroaches) known to inhabit the nests of ants, either commensally or parasitically, and like other myrmecophiles, silverfish have evolved very successful strategies for avoiding detection by their ant hosts. While looking nothing like the ants, as you say, these scaly symbionts are able to blend in with the rest of the colony by rubbing against "callow" or immature workers and adopting the unique chemical profile that sister ants use to recognize one another. In this way, the silverfish enjoy easy access to shelter and resources within the nest and can intermingle freely with foragers on the outside (no doubt pilfering some of the tasty tidbits you observed being brought back to the harvester's granaries). Of course, this chemical disguise is only temporary, so the silverfish must also rely on another characteristic adaptation--speed--if their cover starts to fade, hence their nimble-footedness around the workers.

While some myrmecophilous silverfish are apparently highly specialized, demonstrating a preference for a single ant species, most are generalist interlopers, using their peculiar knack for chemical mimicry to infiltrate the subterranean strongholds of a variety of different ants. Another widespread Mediterranean silverfish species, Proatelurina pseudolepisma, for example, was found in the nests of a total of 13 different species of ants! Those of Messor barbarus, incidentally (the same species in your photograph) happened to be the most popular.

Hope this helps!

Alexandra Westrich & the AntAsk Team

We found these ants below in Anduki (Seria, Brunei):



Hi Uli,

The ants pictured belong to the genus Cataulacus, a group of arboreal-nesting ants widely distributed across the Old World tropics. The exact species is likely Cataulacus latissimus, one of the more sizable of the dozen or so Indo-Australian species, known to occur in West Malaysia, Sumatra, Singapore, and of course Borneo.

Thanks for the photo,

Alexandra Westrich & the AntAsk Team

Dear Ant Team,

I photograph insects...but I do not know ants. Can you help me identify the following species? Thank you very much.

Best regards,







Beautiful images!

The species pictured are most likely (1) Aphaenogaster simonellii, (2) Messor meridionalis, and (3) Cataglyphis nodus.

These IDs were determined with the assistance of guest experts (and AntWeb's own Ants of Greece curators) Drs. Anastasios Legakis and Chris Georgiadis. Feel free to check out the Greece Ants page (linked above) to learn more about the ant fauna from this region.

Thanks for your interest!

Alexandra Westrich & the AntAsk Team

I'm sure you get a lot of questions phrased like my subject heading. But I'm stumped here! I've linked to two pictures I took in the woods in Atlanta, GA.

From the far shot, it looks like the ants are "herding" the insects into a big clump. in the closer shot, you can see that some ants have actually dived into the fray.

Were these ants really herding the other insects or had the insects been swarming beforehand and the ants are just there to pick some off as food?

Also, I can't seem to identify the insects in the pictures that the ants are interacting with. They look like some kind of insect in the nymph stage.

If it matters, the tree in the picture is a beech, I think.

Thanks for your help! I'm so glad I found this blog!


Dear Becky,

Thanks for the great pictures! Yes! Many ant species have facultative mutualisms with aphids (seen here) and other herbivorous insects. The ants guard the aphids from predators, and, in exchange, the aphids essentially poop sugar water into the ants mouths. This "honeydew" as it is euphemistically called, has to be voided from the aphids, because they have to go through a lot of plant sap to get enough minerals and amino acids. To the ants, it's gatorade.

The ants are most likely the common carpenter ant, Camponotus pennsylvanicus. I don't know much about aphids, but those are really big, and they seem to be on the bark of a deciduous tree, so they might be the giant bark aphids, Longistigma caryae. There're probably some other big aphids out there, but this seems to be a pretty widespread, conspicuous species, and they have been reported to associate with C. pennsylvanicus elsewhere in the Southeastern United States.

There have been a few posts about this relationship in other blogs (such as here and here ) and there's a rich scientific literature of ant-aphid mutualisms you should check out if you'd like to know more! There are also some pretty great photos that have been posted by others!

Thanks again for your great pictures!

IMG_4578 (Copy).jpg

Dear Vidarshana,

This really is a great photo! Thanks for sending it to us! The darker ant in the center belongs to the genus Diacamma and the lighter ants surrounding and attacking it are members of the genus Oecophylla. The aggression between the ants may be the result of territoriality, predation, or a variety of other reasons.

Ben Rubin & the AntAsk Team

Hi there!

I've recently observed a bunch of ants on my desk at my lab that seem to "freeze" in movement, in a group, usually in a straight (but not linked) line against the wall, completely stationary for hours at a time. They're usually gone by morning and they tend to return again, usually in the afternoon and the cycle repeats. I've been trying to read up for info on this online but I haven't found any information that explains this. These are small brown ants, common to households, but I'm unsure as to the exact species.

I apologise in advance for the lack of information but I'm extremely curious as to what causes this behavior.

Hope you can shed some light on this.

Thank you

Dear Felicia

The ants you saw are most likely Tetramorium bicarinatum, a species that occurs in houses world-wide. One of the other contributers has observed the "freezing" behavior in other ants, but we really don't know why they do this. It is possible they are responding to vibrations in the object they're standing on, and that freezing might make them less visible to predators. This is a behavior we really don't understand.

Hope this helps!
Jesse Czekanski-Moir & the AntAsk Team


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