Hi guys,

First of all: this blog is really helpful, great work!

So now, while trying to write a report on ants --focusing on aspects of evolution-- I stumble upon many many questions. I'm hoping you can help me out!

1a. Micro-evolution
I was thinking about invasive species that are nowadays found in several continents, like for instance the Argentine fire ant.. Do all of their populations still belong to the same species? (no subspecies)
If so, how come? And would a male and female both from a different continent still recognize each other as potential mating partners or not. (If not, what's the term for that?)

What are specific factors that trigger origination of (sub)species of ants, or what causes the absence of it.

1b. Macro-evolution.. Can we speak of macro-evolution within the ant family, since there are so many different varieties. If not, could the relation between wasps and ants be an example of macro-evolution or is macro-evolution really about even bigger events?

2. Sexual selection
In the mating of ants, is there any 'conscious' selection going on from either gender. Are there species where an individual for mating is picked over another, based on qualities perceived?

Thank you!

Greetings :)

Dear Zoe,

Thanks for your questions! You've gotten to some really awesome, fundamental evolutionary biology questions here, and you're asking me to make generalizations across a family of insects with more than 100 million years of evolution and more than 10,000 species, so I'm not sure I can do them justice in a blog post, but I'll try!

Your sub-question under heading 1a: "what are the factors that trigger origination of (sub)species of ants, or what causes the absence of it," is a question that can only be answered in a very generalizable way: speciation occurs when some factor causes populations of organisms to begin separate evolutionary trajectories. Often, as you suggest with respect to invasive species, this happens because of geographic isolation (allopatric speciation), but there are many theoretical and empirical studies that allude to the possibility of sympatric speciation, which is when speciation happens while populations of organisms are still within "cruising range" of each other. A previous blog post elaborates on speciation in the context of nest parasites.

Your first question about invasive species is great and very timely! There have been at least two studies in the past few years which demonstrated that Argentine ants (Linepithema humile) from different continents actually recognize each other as nestmates! So I can't imagine there would be any trouble with mating there.

The authors of both papers suggest that nestmate recognition is maintained across different continents because there is a steady stream of new arrivals, which prevents the populations from drifting apart. However, the question of when exactly a speciation event happens is very difficult to pin down. In a classic paper on the "Evolutionary species concept," the icthyologist EO Wiley states that "A species is a single lineage of ancestral descendant populations of organisms which maintains its identity from other such lineages and which has its own evolutionary tendencies and historical fate."

By this definition, you would really have to be able to predict the future: how can you know whether a newly isolated population will come into contact with propagules from its ancestral range? The idea that newly isolated populations are incipient species is tempting, but in practice, species can only be delimited if there are morphological and/or molecular differences in them, or, if you subscribe to the biological species concept, things could be argued to be different species if they generally choose not to mate with each other (for more information, you might want to look up pre-zygotic isolation and assortative mating...). In the case of the Argentine ant, I would expect a sudden drop in propagule pressure would result in the actual isolation of the disparate populations, but I would only expect this to happen if humanity drastically changed or ceased its practice of global trade and travel.

Sexual Selection
Speaking of pre-zygotic isolation and assortive mating, I think it makes sense to talk about sexual selection in the context of micro-evolution, because that's potentially a pretty important driver of speciation and trait evolution in sexually-reproducing organisms. Stearns and Hoekstra, an often-recommended text in evolutionary biology, defines sexual selection as: "The component of natural selection that is associated with success in mating." While at first somewhat disappointing, I think this definition is useful because it underscores the fact that sexual selection is a component of natural selection. Many ants form mating swarms, or leks, especially in desert and temperate zones. In these cases, there is a certain amount of "scramble competition," and differential levels of mating success have been demonstrated to correlate with individual traits. However, I am not aware of anything approaching the level of mate choice and the resultant secondary sexual ornamentations that has been demonstrated in some butterflies, odonates (dragonflies and damselflies), or other animals.

For a variety of reasons, the exaggerated secondary sexual traits that seem to emerge in classical examples of sexual selection (i.e., the tail of male peacocks) seem to be less likely to develop in eusocial insects (for a more in-depth perspective on this, check here, here, and here). In lekking species, there is likely to be a very important trade-off between the relative sizes of the flight muscles and the testis and ovaries. Some species of ants do not lek, and either engage in within-nest mating (intranidal mating: for example, some Cardiocondyla exhibit this incestuous behavior), and others engage in "mate-calling," like some moths. For these species, ability to give off (for the females) and recognize mating cues (for the males) is likely to be selected upon, but, to the best of my knowledge, selection on particular traits in these species has not been selected upon. By Stearns and Hoekstra's definition, sexual selection is likely to occur in any sexually-reproducing species, regardless of escalating selection for mate-choice.

I'll defer to Stearns and Hoekstra again for their definition of macro-evolution: "The pattern of evolution at and above the species level, including most of fossil history and much of systematics." By this definition, macro-evolutionary patterns are evident in any taxon above the species level, for example, the fact that genera such as Pheidole, Strumigenys, and Camponotus have many species, while Paraponera, Tatuidris, and Rostromyrmex have very few species is a macro-evolutionary pattern. More ant genera than usual seem to have arisen when the earths terrestrial vegetation came to be dominated by flowering plants, which is another macro-evolutionary pattern.

Traits can also exhibit macro-evolutionary patterns: ants are all eusocial - we don't know of any solitary ants. Asexual reproduction has cropped up several times in a variety of ant lineages, but does not seem to have persisted beyond a speciation event. The ability to cultivate fungus has only occurred once in the ants. The processes that gave rise to these patterns are somewhat outside of the realm of macro-evolution, but the justification for using the term "macro-", instead of referring to these patterns as just plain old "evolution," is that they cannot be predicted by an understanding of intra-specific evolution alone. This is analogous to the anti-reductionist argument that cell biology cannot be usefully predicted by chemistry alone--simply understanding osmosis and organic chemistry would not allow us to predict the utility of sexual reproduction, which in some situations can give rise to heterogamy, which in turn drives the emergence of a fertilization envelope, uniparental organelle inheritance, and, in one case, the tail of the peacock. In another case, irreducible patterns and processes random-walked their way to the population of weird little wasps that would become the ancestors of all ants.

As I said at the outset, one would need quite a bit more time and space to fully answer your questions, but I hope I've at least given you some food for thought.

Jesse Czekanski-Moir & the AntAsk Team


I'm having some trouble identifying these ants I found in my garden today (in Tangerang, on the western outskirts of Jakarta, Indonesia).

I disturbed a small colony of very beautiful ants.

At first I thought they were carpenter ants but on closer inspection saw they were a shiny metallic golden colour all over.

I took some photos (attached), but the resolution is not great (iPhone4), hopefully it is enough for an ID.

Here are some other details on which may or may not help with an ID...

Nest location - by accident I left a mat hanging over an unused light post for 3 weeks (while on holiday). The post (1m) is in the center of my yard (sure under by grass), a few meters away from any plants and garden litter.

It is the monsoon season has been raining almost non-stop while I was away. However the inside of the mat is slightly water proof.

When I returned today I went outside to retrieve the matt to wash it again & discovered a small colony of golden ants living underneath.

They had made a small open nest with some dead grass loosely held together.

I saw a few small white fuzzy balls which I could possibly be eggs - I have only ever seen smooth opaque ant eggs/larvae before.

However when I disturbed their nest (by picking up the mat) the ants did not grab anything to carry with them (I've seen other ants carry their eggs/larvae when disturbed.

After googling everything about golden colored ants the 2 species which were the closest match are:

Camponotus sericeventris
Polyrhachis ammon

But I'm still not sure but have not been able to find any other ants that are shiny metallic gold.

If you have any insight it would be greatly appreciated.

Warmest regards,

photo 3.JPG
Dear Ilsa,

Thank you for contacting AntBlog and sending photos! The ant you found is certainly from the genus Polyrhachis, so we called in the world's authority on the genus, Rudy Kohout. Here is what Rudy had to say:

"It is difficult to say with absolute confidence what species it is, but it is certainly a member of the subgenus Myrmhopla. I also believe that the pics represent Polyrhachis (Myrmhopla) dives Fr. Smith, a very widespread species ranging from south-east Asia south to northern Australia. It is a morphologically stable species with the pubescence ranging from rather abundant and completely hiding underlying sculpturation, to relatively sparse. The colour of the pubescence varies from a rich golden (as on the photos) to rather dull, silvery grey (as in most Australian specimens)."

Polyrhachis ants have some amazing diversity in spines. Click on the link above for the genus or you can also see some of the diversity here.

Keep watching ants!
Corrie Moreau & the AntAsk Team

I am a typical mom who knows only three things about ants: they have structured colonies, they carry 3x their weight, and they invade our home during the rainy season. I had never noticed this behavior before and came upon your website in trying to research if what i think is happening is true. The black ants that I see in my bathroom are scouting for food and I don't kill them because I know they will not find any and will eventually leave, but some lone ants have become lost or stranded and I will see them roaming in the same area for a day or two and then they seem to die. Is it from starvation or cold temperature at night, or emotional distress at being alone with no way back to what they know as home?
Also, when they first invade there are many following a trail but soon I see that some break into groups of a dozen or so that scatter when they detect me, do they communicate in this way? I thought they were more like little robots following programmed instincts so they used chemical scent trails, but it almost looks to me like they are having a meeting to discuss their options. I use Clorox wipes to clean and have looked at the spot were they grouped to make sure there wasn't anything that could have served as food like my son's bubble gum toothpaste. I hope to learn more as I respect these tiny hard workers.

Thank you!
Claudia from central California

Hi Claudia,

Rather than thinking of ants as robots following programs, it might help understand what they are doing by imagining them as small people with a limited view of the world and very short-term memories. Contrary to popular belief, no single individual is in charge of an ant colony, not even the queen. Instead, an ant colony's behavior is accomplished through the independent action of each individual together. So every ant has to use the relatively small amount of information available in the immediate area to figure out what she should be doing. Oftentimes, this means "asking" other ants what they are doing and if they have an opinion on what everyone else should be doing. This type of communication is usually accomplished through antennal contact and scents and could certainly result in the formation of groups of ants all "talking" to each other, figuring out what they should all do next. Of course, it is always a possibility that they just found something interesting on the ground.

The ants that you find in your house are almost certainly looking for food. They could also be exploring for new nesting sites and, as your house is probably relatively warm, it might appear ideal at first. Unfortunately, no matter the reason for their exploration, foraging ants have very high rates of mortality around 15% per day. Many of these ants are the victims of predation or, in hot and dry areas, dehydration, but many simply get lost, as some of the ants in your house seem to. A scent trail may be too faint, may get disturbed, or the ants may get separated from it inadvertently and be unable to find their way home. Their eventual death is likely the result of starvation or dehydration although cold temperatures could certainly be a factor as well.

Deborah Gordon's book, Ants at Work is about how ants get all of their work done and it sounds like the subject might be of interest. You may want to check it out.

Thanks for your question,
Ben Rubin & the AntAsk Team

Ant origins, and beyond...

How far back does speculation go regarding the ancestry of ants? I have found that ants are thought to have come from wasps and I was wondering if speculation went further back to an ancestor for wasps etc. Is there a common ancestor that goes back to the sea?

Another question that I have is rather or not some wasps or wasp like creatures could have evolved from a line of ants, in other words the reverse of the theory that ants evolved from wasps?

Lastly, I am fascinated by ants that have an iridescent or blue hue and I found bees on-line that have an iridescent metallic green turquoise color. Is there an ant with a comparable appearance to this type of bee?


Dear Pamela:

It is fortunate that good answers to at least some of your questions have recently made it into the scientific literature. Let's take them in order:

Regarding distant ant ancestors in the sea, several years ago, David Grimaldi of the American Museum of Natural History published "Evolution of the Insects", an exhaustive treatment of the origins of modern and the many known fossil insects. Grimaldi and all others who have studied the matter conclude from the evidence that the common ancestors of all insects were terrestrial. A number of ancient and modern insect lineages have evolved to live in water for at least part of their life cycle. However, these groups all evolved from terrestrial ancestors. With only a very few exceptions, all aquatic insects live in fresh water, not in the seas, and the few marine insects originated from fresh water ancestors. For a discussion of the evolution of the larger group that contains insects, the arthropods, and where insects fit in this very diverse group, see this blog concerning a recent publication on arthropod-phylogeny. This study indicates that farther back in time, before the insects evolved, all arthropods were marine.

Only much more recently, the wasps, ants and bees arose as a group from more distant, but decidely terrestrial ancestors that looked like insects we call sawflies, also in the insect order Hymenoptera, but with a much older fossil record. There is virtually no question that ants have a common ancestry with wasps and bees, but that each of these named groups have remained separate since the original split. The oldest known ant fossils are dated at just about 100 million years old, but ants as a group are estimated to date back to between 110-130 million years. All available fossil and genetic evidence indicates that since ants originated, only what we could call other ants have evolved from ants, while all modern wasps, since the long-ago evolutionary split from the ants, have evolved from wasp-like ancestors.

And finally, there are indeed a number of ants that have iridescent purple or green reflections. The most striking examples are in the Australian ant genus Rhytidoponera. Once you click on this name, scroll down to R. purpurea for a particularly good example, but others will be worth a look, too.

James C. Trager of the Ask Ant Team

Hello "Askanant". My name is Corinne and I am in 4th grade. I have always wanted to study bugs when I grew up, and I am getting ready to do a science project on ants. (I am sending this message to my teacher, who is also a bug lover too).

Today, I was down in Hemet and playing in a field with my friends. I found what looks like a queen ant. Her face and head look like an ant, but she is almost an entire inch. My dad said he thinks its a potato bug.

There is a picture attached. If it is a queen ant, can you tell me how to try and keep her alive?

Thank you very much!
Corinne, 9 years old, 4th Grade
One day I will get to study bugs for a living!

Hello Corinne:

Thank you for contacting the AntBlog about your mystery insect. A good place to start on your way to "study bugs for a living" is to learn to identify the incredible diversity of insects that live around us, and we're here to help (especially with ants).
We occasionally get questions like yours, about insects with large rounded abdomens, which people think look like queen ants - an honest mistake. It turns out your dad got this one right; the insect in your picture is what many Californians call a "potato bug", but entomologists call a Jerusalem cricket. Here's a link at an insect identification website with some excellent pictures of one: http://bugguide.net/node/view/591927/bgpage. Another group that people often confuse with ants is the oil beetles: http://bugguide.net/node/view/385828.
Two easy clues to recognizing true ants, which can be seen on the many pictures of ants as this site, are:
- "elbowed" antennae, in which the first segment of the antenna is much longer than the others, and held at a different angle to the body than the rest of the antenna
- a definite waist of one or two narrowed body segments. (The Jerusalem cricket has a waist, but it does not consist of a whole body segment, only the narrow front portion of a single segment.)

James C. Trager of the AskAnt Team

The other day I was sitting outside my house with my friend. He and I were just sitting on the ground. There were a number of small black ants around us going about their business but not really in our way. After some time they began to fixate around the area I was sitting. They climbed on my feet and gave little nips and so on. After a while it got a little ridiculous so I moved to the other side of my friend where there were no ants at all. It was completely clear and not in (what I thought to be) their trail. It wouldn't have been more than five minutes later and then they were back again. They were all around me and the spot I had been in previously was completely clear. I just couldn't figure out what it was about me??? I should point out that my friend was left alone the entire time. It occurred to me later however that it had been "that time of month" for me and was wondering if they were reacting to the change of hormone levels?

Thanks for any help you can give me

Dear CJ,

I have never heard of ants being attracted to human hormones before but without doing an experiment, it would be difficult to say for sure what was happening. Ants would be more likely to respond to food smells. Were you carrying any food or had you been cooking recently? A sweet smelling perfume could also be attractive to ants. However, smells and insect responses to them are often unpredictable. For example, certain termites recognize pen ink chemicals as trail pheromones and can be tricked into following ink lines.

Thanks for your question,
Ben Rubin & the AntAsk Team

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

Ant Farm in Saudi Arabia

On Thu, Jan 3, 2013 at 4:33 PM, Allan wrote:


I have twin 4 year old boys who love ants. I brought them back a small ant farm from the USA, supplied with harvester ants from a nature store online. It is entirely self contained, with even edible gel for tunneling that prevents them from needing to be supplied with food.

I am following precautions regarding allowing them to get loose since I don't want to disrupt the local ecosystem. I am curious, are Harvester Ants native to Saudi Arabia?
Apparently they do well in arid regions, and there is plenty of that here.

Thanks & regards,

Allan in Saudi Arabia

Dear Allan:

Thanks for contacting our blog.

The harvester ants that come with ant farms in the USA belong to the American ant genus Pogonomyrmex, which only occurs in the Americas. Here is a nice map showing their distribution:

Since your ants do not have a reproductive queen associated with them, there is no danger they would disrupt the local ecosytem, even if they did escape. But of course, you will wish to keep them contained for the enjoyment of your sons.

Now to your question about harvester ants in Saudi Arabia: Note that Ant Web has a site on the ants of Saudi Arabia:
There are in fact quite a few native harvester ant species in Saudi Arabia, in the genus Messor . These could be suited to rearing in an ant farm, once the ants you already have die off, as they will in a few weeks or months. Here's the page on Messor from the Saudi ants site linked above: http://www.antweb.org/description.do?rank=genus&name=messor&project=saudiants
They are about 1/4 inch long, and some of the species forage in the morning and evening, along conspicuous trails, in unirrigated areas.

It would be recommended, when you put new ants in the farm, that you substitute the gel medium with an inorganic digging medium such as slightly moistened sand or granular pumice. The ants can be fed grass seed, edible grains or hulled, unsalted sunflower seeds. Take care not to overfeed, as the uneaten food will spoil.

Happy ant farming, Stefanie Kautz and James C. Trager of the Ask Ant Team

From: Nancy
Subject: Thatch ants Washington State

We have a red-headed thatch ant colony more than six feet across near
large fir, cedar and big leaf maples. I am told variously that these
ants are beneficials, do not damage homes, are only moderately keeping
of aphids on ornamentals, and while they can bite if provoked, are
not dangerous. All this being said, my question is: Do they in any
way damage the trees, particularly the conifers, adjacent to their
nest? I would prefer to take the live-and-let-live approach and leave
them to enjoy their metropolis. We enjoy watching them and will leave
them alone if they aren't damaging the structure of the very large
trees near their mound.

Thank you in advance for your help.

Dear Nancy:

Thank you for your message to the ant blog. It sounds indeed like the ants you describe are the famous thatching ant, Formica obscuripes. The species abounds in some parts of the western conifer forests, and curiously, also extends south to the sagebrush plains of New Mexico and east to the prairies and old fields of Wisconsin and Michigan! Though it does befriend aphids, this may be considered the plant-to-ant equivalent of the cost of feeding a standing army. F. obscuripes is considered a beneficial insect over all, because of its prodigious predation of plant-eating insects, including such pests as spruce budworm. We applaud your live-and-let-live attitude, and are very pleased you chose to ask before acting.

Best regards,

James C. Trager of the Ask Ant Team

Hi there,

I live in Vancouver, Canada, and am wanting to establish an army ant farm. Can you suggest how best to go about this?


Dear Paul,

Starting an army ant farm in Vancouver, Canada could be very difficult for a number of reasons. First off, by nature, army ants are inherently nomadic predators, and thus keeping them in a confined space such as an indoor "farm" might be next to impossible if you want them to last very long. Secondly, most of the 5 genera of New World army ants (Cheliomyrmex, Neivamyrmex, Nomamyrmex, Labidus, and Eciton) are primarily Neotropical. While some species of Neivamyrmex have been seen as far north as Iowa (see this helpful ant distribution website), Vancouver is still hundreds of miles farther north, and with the cold humidity, it is doubtful any species of army ant could survive. Those that could for a short period would probably be subterranean, and you would need quite an arena to visualize and house a colony of thousands to millions of nomadic predators.

However, in 2005, Dr. Brian Fisher--myrmecologist extraordinaire--was able to import a colony of Eciton burchellii army ants to the California Academy of Sciences for the exhibit "Ants: Hidden Worlds Revealed". The advantage of importing Eciton burchellii in comparison to the many other army ant species is that they're generalists--they'll eat just about anything. The downside is that the millions of workers need a lot of space and have quite an appetite. Dr. Fisher informed me that Cal Academy was feeding the colony over 25,000 crickets a day, which they let loose in a giant chamber housing the colony in the museum.

Thus, unless you have the resources to build an arena and find the appropriate diet (smaller colonies will have more restricted diets--such as ant, wasp, or bee larvae), it might be a difficult task.


Max Winston and the AntAsk Team


In collaboration with

Got a question?

Have a question about ants? Drop us a line!

Recent Assets

  • dorylusnigricansm_casent0172663_p_1_high.jpg
  • cardiocondyla obscurior males fighting_sylvia cremer photo.jpg
  • AZflyer3smallweb.jpg
  • Ant 1.jpg
  • Ant hill 1.jpg
  • Ant hill 2.jpg
  • Ants_egg.jpg
  • Ants_flower.jpg
  • Ants_insect.jpg
  • Major worker.jpg