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We have a sudden ant infestation. Nothing works to get rid of them so we are going to ride it out I guess. Must be the drought in California? I have a question though. They often congregate in our shower. Even when and especially when it is dry in there and no one has showered since the morning. Today, I went in and there were a number of trails leading to perfectly formed circles. The circles had the ants facing inwards and their bodies/tail ends pointing outwards. I wish I would have taken a picture but I was upset and I washed them away. It wasn't a moving circle. It was a stationary size of about a nickel circle. Much like a synchronized swimming event. Is this a meaningful event? Are they talking about leaving my house in this circle? I sure hope so. Thanks for answering me or replying back to my email if you have time. Oh and they are small little black ants - if that matters.


Dear Mary

The ant that is visiting your house is most likely the argentine ant. The move inside when it is too dry outside or too wet. As you have noticed there is many advantages to these visits - one is that you are presented with a convenient chance to observe nature in the comfort of your own home. Why are they forming a circle - well there must have been some resource there - residue from the evaporated water (salts most likely) that the ants were feeding on. If inclined you could give them a drops of water with food coloring in them and watch them change colors:


You can read more about the sudden movement of the argentine ants into homes in California at:

With regard to control, I strongly advise a green approach. First, seal the cracks where the ants are entering. Next if the ants in the house are a problem, then just vacuum them up. Outside if you want to control the nest, apply boiling water (lots of it). Chemicals in your house will be a permanent risk to you and others and outside when applies will be a containment to wildlife and water supplies.

Best, Brian Fisher and the Ask AntWeb Team

Ants in an ant hill

How many ants are in one ant hill?


Dear Samir,

Thanks for your question!

Ants are abundant: they collectively rival with humans as dominant organisms on terrestrial ecosystems, weighing as much as all humans present on Earth; and, combined with termites, they comprise almost a third of animal biomass in tropical terrestrial habitats! The reason for such success is their social nature. More, there are around 16,000 described ants species in the world, and we think there is approximately the same number of species yet to be discovered. As their large species number indicates, ant societies exhibit a diverse array of behavior, morphology, and also nest sizes.

While Myrmoteras barbouri has around 8 individuals in their colonies, some species of nomad ants that live in the old world, A.K.A driver ants, may have nests with several million individuals. Another good example of large nests is the ones built by Atta sexdens, a leaf cutter ant living in the Neotropic, which may possess 5 to 8 million ants!

myrmoteras.jpg Full face view of the charismatic Myrmoteras barbouri, whose nest possesses very few ants. This ant species lives in the Indomalaya bioregion. Image by Estella Ortega/

siafu7-L.jpg Dorylus driver ants in Kibale, Uganda. Image by Alex Wild (

Among the diversity of ants we find on Earth, there are the mound-builder ants. Their nests are more than a pile of revolved soil covering an underground home; they have symmetric shape, complex interconnected systems of galleries and chambers, and are often thatched with leaves and stems fragments, or adorned with pebbles. Those types of nest indicate habitats under extreme climate. The mound reduces the loss of temperature and humidity, while it also increases the area exposed to sunlight, keeping the nest warmer than the outside environment. Their thatched or pebble sprinkled roofs are an additional heat source (think of how warm is a stone under the sunlight, or the heat produced by material in decomposition), besides preventing evaporation.

FormicaObscuripesNest-S.jpg Thatched mound nest of Formica obscuripes, an ant found in North America. Image by Alex Wild (

The nests of some mound-building ants, such as Formica (also known as wood ants), often last for many decades, and they can be massive, rising from the soil surface as much as 5 feet (1.5 meters).

A thatched mound nest of Formica rufa, found in Palearctic region, may have 4 million ants; while in North America, nests of the western thatching ant Formica obscuripes, house around 40,000 ants. The soil mound nests of Solenopsis invicta possess approximately 100,000 individuals.

casent0178134_p_1_high.jpg Lateral view of Solenopsis invicta, a tramp species found in the United States. Image by April Nobile/

You will find interesting information on mound nests and thermoregulation here.

All the best,

Flavia Esteves & the AntAsk Team

Ants and Disease

Hello, this is a very strange situation but I have a 10 month old baby in my home and I am concerned.

A couple of weeks ago I went in to the backyard and noticed my dog was playing with something unfamiliar. As I walked towards it I realized that it was a bird. This bird must have been there for awhile because it was unable to move, and had defecated so much that ants were (I'm sorry for the graphic details) actually crawling inside of this poor bird and apparently eating the fecal matter. This poor guy was obviously in a significant amount of pain so we had to do something very sad to stop it from suffering any longer.

This just so happened to have occurred next to a wall in our home that is the exterior wall to our dining room where we eat and where my 10 month old's high chair is. Today, I was eating at our table and some of my paper work and pens were sitting on top of it. As I was picking up my plate I noticed the same species of tiny little ants crawling all over the table and my paper work. There was not even any food or anything on the table that could have lured them there. I instantly took my son upstairs, and began disinfecting the table, vacuuming and such.

I do not know anything about ants but my concern is that these ants might be carrying disease from the bird. Can you please tell me if I need to be worried about this? They are the tiniest little transparent orangish colored ants. We live on Oahu, in Hawaii. Thank you very much for your time.


Ok, Alix. I've got good news and bad news.

The bad news: Ants (just like any animal that moves from one place to another) can transmit infectious bacteria, including Salmonella and Staphylococcus. (I'm not trying to throw your dog under the bus by any means, but your dog is definitely more of a vector for bacteria coming in from outside than these ants.) As indicated in a quick literature search (click here ), it's been reported at least as far back as 1914 (Wheeler) that if an ant walks through an area densely populated with infectious bacteria, they track it along in quantities large enough to show up in a petri dish.

The good news: Petri dishes don't have immune systems. The quantities of bacteria ants transport and slough off as they saunter across your counter tops will probably be small compared to the infectious dose for healthy humans. The quantities of bacteria that remain on the ants' feet after taking the thousands of little ant-steps between a source of infection and your table would presumably knock off the vast majority of the bacteria, leaving too few to constitute an infectious dose.

So what I'm trying to say is: thought it is theoretically possible for ants to transmit infectious bacteria to humans, as far as I'm aware (other members of this blog, please speak up if you know better!) there are no records of ants being definitively implicated in someone catching a disease. As best as I can tell, all of the articles that reference ants' potential to be vectors for infectious bacteria are based upon laboratory studies in which nothing besides some agar in a petri dish got sick. Ants, as you know, are quite common, so it seems to me that if they were serious actual (as opposed to potential) disease vectors, we'd have heard about it.

A well-intentioned tangent: This is, of course, neither a child-rearing nor a health advice blog, but I think this recent article on the "Hygiene Hypothesis" makes a good case for not keeping too sterile a house:
Some arguments, both pro- and con- Hygiene Hypothesis haven't been rigorously scientifically tested, so take everything you read with a grain of salt...or a pinch of dirt.

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

Ants in concrete foundation

Hi - and help!?

We live in Northern Alberta, Canada. Over a year ago, we discovered ants - lots of ants - coming up into our furnace room through a crack in the concrete foundation of our basement. My husband put poison down the crack and seemed to work very well, getting rid of them and not coming back. Until now.

Last night he went to check - as he does periodically - and now they are large ants coming from the same crack in the concrete. He again put poison down the crack, and vacuumed up the few dozen (he may have been lessening the amount to avoid my freak out). My daughter's bedroom
is right beside the furnace room. She went to bed last night - only to be woken up by something flying and hitting her in the guess is a flying queen ant.

Please tell me what we should be doing to ensure we have gotten to the bottom of this ant problem. Should we get the crack filled? Will they find another place to come in? In order to get access to this part of the foundation concrete, they have to be coming in very deep under the back yard as that part of the foundation must be at least 6 feet underground.



Hello Cathi,

Thanks for writing to the AntBlog!

Ants are an important part of the natural world, and play a great role in an ecosystem. Their extreme diversity and abundance, wide spectrum of biology and interaction with other groups of organisms, make them affect the pattern of distribution and abundance of plants and other animals. The good news is that this is also applicable to your home environment: ants will control populations of other housemate arthropods, like spiders, fleas, clothes moths, bed bugs, and so on. We can also learn a great deal with ant behavior (to see how ants have inspired human societies, take a look here).

Full face view of Polyergus breviceps, a slave maker ant species that occur in your area (image by Shannon Hartman/ See more on how it makes slaves here.

So, if it were my home I would just control their population, prevent them from accessing my food, and marvel myself with them crawling around. Procedures like proper food storage and waste management, and daily surface cleaning, will reduce the number of ant workers indoors.

However, if you really cannot live with those wonderful creatures, I think the most effective way to prevent them from accessing your home would be to seal the cracks (you can use clear silicone, or other sealant).
Please, note that commercial sprays are ineffective against ants, killing just the foragers, while the rest of the nest (deep underground) continues intact. Poisoned baits generally work well to eradicate ant colonies (workers feed on the bait and take it back to the nest where they share it with their nestmates), but this approach may take several weeks to several months to produce an effective result. You can read more on baits here.

We hope it helps,

Flavia Esteves & the AntAsk Team

Ant social status

Hi, I was curious if ants have a social status within their sub sectors (worker, male). How do they obtain a higher status? And if so does this give them more privilages (ie a bigger living space, more food, first breeding rights).


Dear Hub,

Thanks for writing to the AntBlog! We contacted an expert on many aspects of ant biology (behavior, colony reproduction, nest architecture, population dynamics, among others), Dr. Walter Tschinkel; here is what he had to say:

"Hello Hubert,
You asked AntBlog whether ant have social status within their colonies, and whether such status might be connected to certain individual advantages and benefits.
The simplest answer is that social status in the sense that we know it within vertebrate societies does not exist in ants. It is helpful to think of ant colonies as analogs to organisms (hence, we often call them superorganisms). Every individual is engaged in helping the colony produce more colonies, just as every cell in an organism is engaged in helping produce more of that organism. In the ants, there is only one (or a few) individual(s) capable of direct reproduction (the queen), while in an organism, only the germ-line cells in the gonads are capable of making gametes and subsequently more organisms. In this light, you can see that different sectors of the colony may be allocated differing amounts of resources, but such allocation serves the needs of the colony as a whole, rather than any individual within it. The individual ants making up the colony are simply the machinery needed to make more colonies.
One of the basic mechanisms that organizes colony function is division of labor (or function). The most basic division of function or labor is reproductive -- most of the ants in a colony are more or less sterile workers, while only one (or a few) individual is capable of mating and laying eggs. Most of these eggs develop into more workers because workers are short-lived and are continuously replaced, whereas the queen has a long life span (in many cases, equal to the life span of the colony). The second principle that organizes the colony is that the workers change jobs as they age. Young workers mostly take care of larvae and pupae, and as they age they switch to more general nest maintenance, food processing, transport within the nest and so on. Only the oldest workers leave the nest to forage, bringing back food for the rest of the colony. Once they begin foraging, their life expectancy is very short (a few weeks).
This change of jobs parallels an upward or outward movement of the worker within the nest. Young workers are born in the deeper parts of the nest, move upward as they age and change jobs, and finally appear near the surface, whereupon they become defenders and foragers during the last part of their lives. There is thus a continuous upward and outward flow of workers. The image here shows a cast of the nest of the Florida harvester ant, Pogonomyrmex badius, and summarizes these movement and labor patterns within the nest.

Once you see the parallels between organisms and superorganisms, you see that division of function or labor is central to both, and that differences in allocation serve the entire entity. The relative size and activity of the liver, or kidneys or circulatory system of an organism serves the entire organism, and any deviation from some norm can be detrimental to the function and fitness of the organism. Similarly, the patterns of division of labor in ant colonies serves the success and fitness of the colony as a whole. The workers are just the gears in that machine."

We hope this answers your question,

Walter Tschinkel, Flavia Esteves & the AntAsk Team

My name is Joseph, a senior biologist at the University of Scranton. I am currently conducting research on morphometric of ants, but we are having some issues. I was curious if you had any papers on the histology of ants, specific on the nervous system or their notochord. Any species will do at the moment, we are just used to looking at mammalian tissue, and not insect samples. Hope to hear back from you soon!


Hello Joseph,

Thanks for writing! We contacted an expert on the nervous system of ants, Dr. Wulfila Gronenberg; here is what he had to say:

"Dear Joseph,

the nervous systems of insects has been well described for many taxa, and ants are no exception. The basic design is not unlike what you see in vertebrates - they have a brain with visual, olfactory, tactile and other centers including higher order central processing centers, and the have a ventral nerve cord analogous (and probably homologous) to the vertebrate spinal cord and which comprises the sensory and motor centers that control walking, flight (in winged males and females) and abdominal functions. If you want to learn more about ant nervous systems I suggest a review paper that I have written a few years ago:

Gronenberg W (2008) Structure and function of ant (Hymenoptera: Formicidae) brains: Strength in numbers. Myrmecological News 11:25-36.

If you (or anybody else) have difficulties getting hold of the paper, just send me an email:
If your question was more about histological and technical aspects (how to dissect, stain or measure ant brains), please let me know and I can point out some more specific information to you.

All the best"

Wulfila Gronenberg, Flavia Esteves & the AntAsk Team

p.s. Joseph, if you create an account on Myrmecological News (for free), you can download Gronenberg's paper.

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

Neighborhood ant farm?!

I have an ant infestation in my house and I have just begun terro traps. I have already attempted an ant killer by black flag but unfortunately that failed because they weren't attracted to it. I was speaking with one of my neighbors today and it seems that they have the same issue. Also the same issue for a neighbor that lives a street over. I'm worried that the traps are nothing compared to the abundance of ants. Any advice on getting rid of them?


Dear Cortney,

Thanks for writing! Regarding your question: since your traps are not attracting the ants living in your house, I would try something like a cafeteria experiment. It consists of offering them an array of food items that they might eat on (e.g. peanut butter, jam or jelly, and tuna). Once you discover which item works better, add the appropriate poison, and set the traps. You will find really important information on traps and baits here.

However, ants are quite important for our surrounding environment, providing services like bringing nutrients to the surface of the soil, aerating the soil, dispersing seeds, and predating pest species. Many of them are beautiful too (like our special guest here). I hope you will fall in love with them while observing their interactions on your baits, and find a way to coexist with them!

I hope this helps,

Flavia Esteves & the AntAsk Team



I stumbled upon your site while googling 'how to make peace with your ant infestation' (there seem to be no suggestions on that, by the way). I thought perhaps someone could offer advice for our particular situation.

I live in south Florida. In March, my husband and I bought our first house. Before closing, I did see a pile of dead ants in a corner of the family room, but the home inspector's report didn't find signs of any infestation, or at least 'wood destroying organisms'.

Once we moved and settled in, I began to realize that there were serious ant colonies on the property, and noticed ants in the Florida room, also in one of the bathrooms. I think in the beginning, they were all dead ants on the window sills and in that bathtub. As summer progressed, the problem got a bit worse. They can walk right through our windows and front door.

I did a bunch of online research, and I'm thinking they are carpenter ants. Not as big as the ones up north, but carpenter seems to fit the description. Because I have a toddler and two cats, my first line of defense was a borax/powdered sugar mix. I scored a big hit when I found old timbers half buried in the front yard near the walkway and removed them, and also pored boiling water at the foundation under a window in the back. We also replaced the weather stripping at the front door, and I've been caulking baseboards and around windows. For about a week, maybe two, it seemed like I was making some real progress, however this morning I saw ants swarming again out front in the morning. Late this afternoon I noticed ant hills surrounding potted plants in the back (near the house). I shook the pots a bit, and ants also started swarming out of the pots, up the trellis, and carrying eggs up into a previously unseen hole in the eave. Great.

I'm not positive, but I think the ants I've seen over the last few days are smaller than the originals, so maybe these little guys have stepped in to fill the void of the bigger ones. Regardless, we have ants in our walls, and apparently in our attic. I know that to truly keep these guys out we have to replace some rotting wood at the door in the back, but our windows are so old that they can literally crawl right through them - the windows themselves, not gaps around them. I have a little one and a couple critters that prevent me from putting down serious poison, and our budget is falling a bit shy of relaxing the doors and windows.

Is there any advice you can give on how to begin to win this battle? The house was empty for a long time, and the responses of ants in different areas let me know that's it's a big ass colony, or that the satellites have close communication.. Any hope you can give me is greatly appreciated-


Dear Alyssa,

Thanks for writing! I am glad you are still trying to make peace with ants that live in your house. Most ants are beneficial for our surrounding environment (including yards) - they actually rule our terrestrial world: cycling and bringing nutrients to the surface of the soil; aerating the soil; dispersing seeds; predating pest species, among many other "services". Also, children generally like to spend time observing ants just pass by, or being attracted to a bait, and it can stimulate their curiosity towards our natural world. You can read more about how good ants are here.

If after all you think its better to get rid of your crawling roommates, you should know you are already doing some of the most effective things to eradicate them from your home, and here you will find important information on baiting. Further, you can drown ant colonies in the plant pots, using warm water, and leave some clove sachets in strategic areas of your home (like in the food shelves) to repeal them.

If you really have carpenter ants, this may indicate you have a more serious problem, because they often build nests in compromised wood. I would first be sure they are really carpenter ants - try this and this for identification; and, if positive, you can try this to eliminate them from your place.

Please, look for more tips here, and have a good lucky in your endeavor!

Flavia Esteves & the AntAsk Team


I came across your interesting website and I wanted to find out if there are any images available for what ant dung looks like.

Many thanks,


Hi Cristina,

Thanks for your question! I have to admit, although I've spent a fair amount of time looking at ants, they're usually either dead or foraging: I've never caught one in the act, so this was a fun question for me to try to answer. Luckily, I have access to some other people with lots of ant experience, so I'm able to share their insights.

First, though, let's start with some terminology. When insects eliminate undigested waste, it's called "frass." This is a general term, that also (depending on who you ask) encompases other little particles and exudates that result from insect activities. For example, wood dust that results from carpenter ants gnawing through wood is sometimes considered "frass," even though the carpenter ants don't actually eat the wood - they just cut through it. Since your question is obviously directed towards elimination, we'll focus there.

Something about ants that many people don't realize is that as adults, they are unable to consume big chunks of food. Their jaws are often good at holding and/or cutting through objects, but not well-adapted for chewing food into pieces small enough to swallow. Some ants can eat pollen grains, but solids much bigger than that will not pass through the narrow constrictions at an ant's neck and waist. In a peculiar reversal of the "mamma bird" situation we've all seen on nature shows (and in real life, if you're lucky), adult ants must bring solid foods back to the nest, where the ant babies (larvae) eat it, and then vomit some of the chewed and partially digested food back into the mouths of the adults.

Because adult ants never eat solid foods, their frass tends to be a dark-colored liquid--at least as far as the ants that AntAsk Team members Corrie, James, and Steffi are familiar with are concerned. They (the ants, not the people) also excrete metabolic waste, analogous to urine, in the form of white urate crystals, which James describes as mixing together with the feces in various proportions: "sort of like coffee creamer."

The ant larvae, however, are a different story. They only eliminate waste once during their development, in the form of a dark, compacted mass (can I say "turd" on this blog?) shortly before pupation. This cuts down on diaper changes considerably. Interestingly, albeit disgustingly, sometimes adult ants eat this meconium (reported in Cerapachys biroi by Ravary and Jaisson 2002, and Cephalotes rohweri by Creighton and Nutting 1965). I apologize if you're reading this right before a meal.

As I wrap up this post, I realize I haven't actually pointed you in the direction of any real pictures. There are some pictures of meconia among Alex Wild's excellently curated collection of ant pictures, but I'm not aware of any pictures of an adult ant in the act of defecating. Refuse piles in subterranean ant nests, and below arboreal ant nests are more commonly photographed, but they often contain the bodies of dead workers and discarded prey parts, in addition to frass in the strict sense. So the best I can do is leave you with James' vivid image of a fine white powder mixing into a dark drop of liquid, like creamer into coffee. If I find a good picture of an ant in the act of "frass-ing", I'll let you know!

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

ps. if you're interested in other things that come out of ants, please see this previous post about ant pee:


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