Hello,

I stumbled across your very interesting blog whilst searching for an answer about ants.

We live in the sub-tropics (Queensland, Australia) and just over a week ago experienced severe wet weather (flash flooding) due to an ex-cyclone passing over us. This was after an extended period of dry weather in a hot Summer. We have had a steady stream of various ants come in due to the weather, mostly heading for the kitchen. This is quite normal for us and has been managed mainly by keeping minimal accessible crumbs etc.

The unusual ant activity we've had is in the last couple of days. One night we suddenly realised that there were clumps of tiny black ants all over the house. There were thousands of them in the laundry, on the top of the wall and cornice - not many down near the water sources at all. There were also about 6 big clusters of them located on cornices throughout our living room and hallway - far from any food source and/or water. The next day another cluster appeared on the door frame of our bedroom en suite - these ones were near some artwork and some were feasting on the glue used in it, but most were in clumps on the doorframe. I took some pictures and have attached them.

Ants1 is to give you a reference point for size and the shapes of all the small clusters these ants are forming - these are very small ants compared to most others we get locally.
Ants2 is a closer shot - when I was later looking at the photos I noticed that the ants appeared to be clustered around some sort of larvae or white-fleshed ant? I suppose this is why they are clumping, but am wondering what the white things are. I am hoping it is not termites! I am also curious as to why these ants all suddenly appeared in such unlikely places (and so many times) particularly given that it had been about a week since the wet weather. I would also like to know what we can do to try and discourage them from invading our house in such a huge and sudden manner.

I've done some searching on ant identification pages etc. and the closest ant I can come up with that they may be is the "black house ant". Although I am not sure they have the right number of joins in their body.

Any answers to my questions would be much appreciated!

I can send a bigger sized picture if you require it, just let me know if you do need it. I just didn't want to unnecessarily overload your inbox with a large sized file.

Thank you,

Anna.

Dear Anna,

Thanks for the question and the pictures!

First off, these are definitely not termites. Note the "elbowed" antennae and distinct rear part of the body (called the "gaster" in ant literature).

These ants probably belong to the genus Technomyrmex. They're very common in forests in tropical Southeast Asia and Australia. I used to work on a small group of islands called Palau, and there were parts of the forest where it seemed like nearly every tree had this density of Technomyrmex on them. Although it's tough to say for certain, it's likely that these ants belong to a group of very similar-looking species that would have all been identified as Technomyrmex albipes a few years ago, but have since been shown to belong to several distinct species, including T. difficilis (guess why it has that name!). Here are some close-up pictures of the ants I think you have (although this this ant is fairly widespread, these pictures were actually taken in Queensland). In your region, many common household ants can be identified using a key developed by Eli Sarnat for the Pacific Invasive Ants program out of New Zealand (assuming you have a good microscope). For more complete information on ants in your area, check out our Queensland section on AntWeb, and Steve Shattuck's Ants Down Under.

We've written a few posts about getting rid of ants in and around your home (for example: here, here, here, and here), but in your case, one of the more important actions might be keeping vegetation from touching your house. I've actually seen a house in Palau that was entirely on concrete stilts, and each stilt rested on a concrete block that had a small moat of water in it - this is essentially the house-level equivalent to putting the legs of your kitchen table in tuna cans filled with water to prevent ants from climbing up. However, the house got electricity from an above-ground wire, and there was a steady stream of Technomyrmex coming in on that wire all the time! So....I guess there's only so much you can do!

Hope this helps, and good luck!
best,
Jesse Czekanski-Moir & the AntAsk Team

Hi,
I am doing a class project on ants and I am just wondering is there anything that ants do not like to build nests near or close to, I know they like to build nests on geopathic stress lines but is there anything that they don't like to build on?
kind regards,
Joseph

Hello Joseph:

Thanks for your question to the Ant Blog! For the first part of my response, I'd like to say that different sorts of ants, among the almost 14,000 species known, have different nesting preferences. So, for example, one would not find characteristically arboreal ants nesting in soil, nor would soil ants nest under bark of a living tree. Some species prefer particular soil types, such as sandy and well drained, or dark, moist and rich. At larger scales, grassland ant species are unlikely to be found nesting in a forest, nor tropical ants in a region with a winter season.

But, I'm guessing that your question refers to species of "generic" soil-nesting ants. These often appear not very fussy about where they locate their nests. Such ants may be found nesting in soils with all sorts of textures and moisture levels. Studies have demonstrated that there are ants nesting at nuclear bomb test sites, where toxic metals have been mined, and areas reduced to ash and heat-sterilized soil by wildland fires. I've even found nests of ants in soil so toxic that no plants could grow in it, on military land, created by incineration of "unexploded ordinance".

On the other hand, one consistent pattern I've noticed over the years is that soil nesting ants do not usually nest in soils that are compact and saturated (covered with water) after rains. For example, the lawn around my house has patches with numerous ant nests, and others where there are none. After heavy rains, it becomes clear that the ant-free zones are slightly lower, and water pools in them for a while before soaking into the ground or evaporating.

James C. Trager of the Ask Ant Team

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 :)
Zoe

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.

Macro-evolution
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.

best,
Jesse Czekanski-Moir & the AntAsk Team

Hi,

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,
Ilsa

**********
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

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?

Pamela

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
CJ

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

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

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

Greetings,

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:
http://www.antmacroecology.org/ant_genera/Pogonomyrmex.html

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:
http://www.antweb.org/saudi.jsp
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