Hi,
I'm a writer, currently working on a children's story which includes an ant anecdote.

In the story, I have six ants carrying a strawberry at a strawberry farm. They carry it about 3 yards (past a child who is watching) to their anthill.

I don't want to include anything in my story that couldn't really happen. Could this scenario happen? If not what would be more likely? Less ants? More? Would they cut the strawberry into tiny pieces before carrying it?

Thanks so much for your help.
Sara


Dear Sara,

It is a very nice image! But I have never seen a group of ants carrying a strawberry. If it were very ripe, most ants would simply drink the juice inside of it. Ants tend to put more effort into bringing food back to the nest that is rich in proteins and/or fats. The major exception to this rule is the leaf-cutter ants, who use leaves or other things to feed their fungus gardens. Leaf cutter ants, especially those in the genera Atta or Acromyrmex, would happily cut up a strawberry into liftable pieces and bring those back to their nests, like this picture of an ant carrying part of an apple.

Unlike other ants, these genera of leaf cutter ants need the cellulose in leaves and other plant parts to feed their fungal gardens. The reason most ants bring food back to the colonies is to feed to their larvae; not only do the baby ants need food to grow, they are also the only ones in the colony who can chew and swallow solid food! Adult ants can sip water and other liquids, but they cannot chew food up into small enough chunks to pass through their narrow necks, so they bring large chunks of food back to their babies, their babies chew the food, swallow it, and then regurgitate the partially digested food back into their older sisters' mouths! For this reason, larval ants have sometimes been referred to as the "digestive caste" of the colony.

Leaf cutter ants actually have two "digestive castes": their fungal gardens, which digest leaves and other vegetable matter (in the case of the two genera mentioned above, at any rate), and their larvae, which chew, swallow, and regurgitate the fungus. For ants that don't grow fungi this way (including other genera of "leaf cutters" that actually use insect droppings or dead animals to feel their gardens), they wouldn't bother bringing such a sugary, cellulose-rich source of food back to the nest.

I personally think it's ok to take a few artistic liberties with children's literature. It's not impossible that some Atta or Acromyrmex would carry an entire strawberry back to their nest, and then cut it up there. But it seems much more likely that they would cut it up on site, and then carry it.

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

Hi!

I am battling hordes of very small ants in the walls and under the floor of an old house. They are too small to be carpenter ants or fire ants.

They instantly find any food and get into containers I would have sworn were unassailable. I tried to ID them, but every ant species I thought might be them is said not to sting or bite - and these DO.

They don't raise a huge welt like a fire ant, but it is a very distinct sharp needle-like prick. I haven't managed to stop myself from slapping at them in time to see if it is a sting or a bite. They are quite small (1/12th of an inch, maybe? tops?) and translucent orange in color, with a slightly darker brown dot on the posterior.

I also get very large solid black ants in one room of the house - also from under the floor or through the wall.

Any idea what they are?


Dear Sarah,

I'm sorry to hear about your problem. Normally I enjoy watching ants go about their daily activities, but I have also had some experience with tiny stinging ants like the ones you've described, and I would want them out of my house, fast.

So, first things first, there are some measures you can take before you call the exterminator. We describe how to get rid of ants in your home here.

Second: What are these ants? There are three species I can think of that more or less fit your description that have established reputations for themselves as world-wide pests. They're all stingers, so no need to stop slapping:
Monomorium pharaonis,
Monomorium destructor,
Wasmannia auropunctata.

Monomorium destructor might be the easiest to tell apart from the other two. Its workers are conspicuously polymorphic; that is, when you see a lot of workers together, there will be some that are different sizes. The largest workers will be almost twice as big as the smallest workers, and there will be workers of intermediate sizes. They are usually orange-brown in front with a darker gaster (the gaster is the last major part of an ant's body). Monomorium destructor earned their species name because in addition to having a painful sting, they are very good at chewing through things like plastic bags, clothing, and even the insulation around wires. If you notice a lot of holes in things near where the ants are, then there's a good chance you have these ants.

Under a microscope, it's easy to tell the remaining two ants apart. There are numerous differences, perhaps most obviously the large spines Wasmannia auropunctata has projecting off the back of its mesosoma (the middle body section of an ant). Without a microscope, however, it can be difficult to distinguish the two. If you saw them side by side (or fighting!), you would notice that Wasmannia has a shorter, more square body shape, and is about the same color throughout its body. Monomorium pharaonis has a longer, more slender shape, and it usually has a darker gaster, but on both ants the color can be variable - Wasmannia can have a dark gaster, and M. pharaonis can be all the same yellow-brown color. Wasmannia auropunctata is sometimes called the "electric ant" because of its uniquely scintillating sting. Unless you're a real connoisseur of ant stings, though, it might just feel like another painful annoyance.

Looking at the pictures I linked to on the web might help, but really the best way to get a confident identification of tiny ants is with a microscope or a very, very close picture.

As far as I know, of those three ants only Monomorium pharaonis has been reported from Texas (based on the list published on AntWeb here, and an older list by Wheeler and Wheeler here), but Monomorium destructor and Wasmannia auropunctata are both very good at dispersing with humans. You haven't just come back from a fun trip to a tropical island by any chance, have you? Both Wasmannia auropunctata and Monomorium destructor can be quite common in Southern Florida and the Caribbean.

I hope this helped.
Best,
Jesse Czekanski-Moir & the AntAsk Team

Hello,

I am junior that studies my local ants as a hobby. One question that has been bugging me recently is about  Tetramorium sp. E. I understand that until recently it has been considered to be T. caespitum and introduced from Europe like all other species of the genus except the desert species T. hispidum and T. spinosum. If there are only 2 desert species found in North America, how did they get there and why didn't the genus spread to other types of environments? I was wondering what evidence shows that T. sp E is an introduced species like T. bicarinatum or T. tsushimae, how and when it arrived, and if there is a possibility it isn't introduced.
                                                                                                                                                Joey, Mansfield MA


Dear Joey,

"Where in the world did this come from?" is the basic form of many questions in the field of biogeography. To answer it, scientists use evidence from the fossil record, molecular biology (usually DNA), and the structure and form of living organisms (morphology).

Fossil evidence is often the best, but most ant species don't have a fossil record (although there are many ant fossils, there are not enough to provide back-stories for the more than 14,000 described ant species!). Molecular biology can be very useful in tracing the ancestry of organisms, simply because it provides the most accurate way of re-constructing their family tree. If the most distantly-related members of the group of organisms you're studying all live in the same place, we often assume that place is the origin of the group. For example, the most diverse genus of ants, Pheidole, was shown by Dr. Corrie Moreau to have originated in the New World (North and South America). She used evidence from DNA sequences to show that the most distantly-related groups within the genus were all found there, and almost all of the Pheidole found everywhere else were part of one (relatively) closely-related group. Using this evidence, she reasoned that this is where they must all be from (actually, it was much more complicated than that--she used a lot of statistical analyses and sophisticated software to arrive at that answer. You can read more about it here).

In 1957, myrmecologist Bill Brown published a short piece entitled "Is the ant genus Tetramorium native to North America?"
in which he presents evidence that is more or less a well-reasoned series of anecdotes for the idea that Tetramorium sp. E (which was, at the time, T. caespitum) is not native to North America. For example, he argued that because it is only common in very urban settings in North America, whereas in Europe and Asia it is often found in more "natural" settings, the latter was more likely to be its natural habitat. Although not bullet-proof, this line of reasoning does make sense. As later authors have shown, Brown was probably not actually collecting the same species in all the places he travelled. It would be interesting to go back to his old collections and figure out what species he really got!

In 2006, Dr. Birgit Schlick-Steiner and several colleagues published a paper in which they provided evidence that individuals in what was previously considered Tetramorium caespitum (and the difficult to distinguish T. impurum) were actually members of at least seven different species. They used data from DNA sequences, chemicals found on the outside of the ants (cuticular hydrocarbons) and the way the ants look (morphology). Usually, in situations like this, authors will provide names for the newly erected species. But members of the Tetramorium caespitum group had been described under roughly 50 different names in the past, and the strict taxonomic convention dictates that they have to be assigned the first given name. Rather than attempting to find and re-evaluate all the relevant type material, they decided to simply go with a series of letters. (it should be noted that, at the time of this writing [January 2011], the majority of images of Tetramorium caespitum on AntWeb are actually of Tetramorium sp. E).

This study supported the idea that "pavement ants" aren't native to North America by showing that there were a cluster of closely-related, but distinct species in Europe, and, within that cluster, one very closely-related group in North America. Such close relationships over a very wide geographic area (across the US) strongly suggest a recent introduction. Although it is at a much finer taxonomic scale and grain, this reasoning is analogous to that used in Moreau's study of Pheidole described above.

There are collections of T. sp. E from the United States dating back to the early 1900s, and possibly before, so it was introduced before that, but (I would guess) probably not before the 1600s. Interestingly, there is also a species of ant that doesn't ever have workers and has to live as a nest parasite of Tetramorium sp. E, called Anergates atratulus. The most likely way that this species was introduced was with a whole or partial colony of Tetramorium, perhaps in some construction materials or ballast brought over from Europe. Both species may have even been introduced more than one time. In fact, Schlick-Steiner and colleagues' 2006 study showed DNA evidence of at least two separate introductions.

Regarding your questions about the truly native Tetramorium species in Americas, the desert relatives of the pavement ant, Tetramorium hispidum and T. spinosum are in the same genus, of course, but they are actually quite distantly-related, and have likely been present in North America for millions of years. The idea of a 'genus' is tricky, because it is not comparable in very different groups of organisms. Most of what we think of when we think about different species within a genus are mammals, and have only been separated for 10 million years or less. But really, many insect genera are actually about the same age as the majority of what we call "orders" within Mammalia (both are often around 65 million years old, give or take 15 million years). Thus, just because Tetramorium sp. E was suited for life as a pavement ant in cities across North America, doesn't mean that its very distant cousins are.

How do we know that they're native to North America? The best evidence is that they are distinct, recognizable species that have never been found anywhere else. Actually, for a long time, our native Tetramorium were classified in a different genus, Xyphomyrmex. In addition to the desert Tetramorium present in the US, there are three closely-related species in Mexico (T. bicolorum, T. placidum and T. mexicanum), and although there isn't any DNA evidence to prove it, based on the way they look, the closest relatives of the native New World Tetramorium (also formerly members of the genus Xyphomyrmex) are probably in Africa.

Why are our native Tetramorium in the desert and not in the Great Plains or the Boreal Forest? Well, why are cactuses and road-runners mostly in the desert? It is an unsatisfying answer, and like Bill Brown's paper, mostly based on anecdotes and reasoning, but most species, even when they disperse, tend to be most successful in habitats that closely resemble those of their ancestors (the formal, testable version of this statement is called the "Niche Conservatism Hypothesis"). Thus, most invasive species tend to do well in habitats that closely resemble their own. It is possible that the ancestors of the native New World Tetramorium were blown here, or washed ashore from a desert area in Africa. This may have even happened when the continents of Africa and South America were closer together--we could test that hypothesis with DNA sequence data. Tetramorium sp. E, on the other hand, was from a climate more similar to many of the non-desert areas of the United States, and this is where it has been successful.

Interestingly, we can't entirely rule out the idea that the New World Tetramorium never diversified into other biomes, only to subsequently go extinct, perhaps during an ice age. All we can do is shrug our shoulders and say, well, we have no evidence to suggest that they ever did. And when asked why, shrug our shoulders again and say, dunno, really. They just didn't. When the distribution of a species or group is not due to currently operating behavioral or ecological processes (like natural selection), we call this a(n) historical contingency (there are many other types of historical contingencies, perhaps most famously explored by Stephen J. Gould in his book, "Wonderful Life"). They're fun to think about, and propose explanations for (an activity often called "hand-waving," by academics), but ultimately unknowable, at least with the data and methods we have available today. "How did [Tetramorium] get there and why didn't the genus spread to other types of environments?" Is a really great example of such a question. With more molecular evidence, we could say roughly when they arrived, and where they were likely to be from, but we'll never know exactly what transpired when they dispersed here.

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

Can ant colonies reproduce and sustain with no queen? And what is the role of the queen in the actions of the other ants? Has it been found to have any instruction, or only egg laying? (Angela, Baton Rouge, Lousiana, USA)


Hi Angela,

In a "typical" ant colony, there is one or several queens that have been fertilized on their mating flight before colony founding. These queens lay eggs. The queen can lay fertilized eggs, which will develop into females (workers or - when the colony is mature - workers and new founding queens). The queen can also lay unfertilized eggs, which then develop into males. If there is only one queen per colony and this queen dies, the workers can start to lay eggs. But since the workers have not been fertilized, these eggs only develop into males. Males don't contribute to maintaining the colony, they will fly off once mature to mate. So the "typical" colony cannot sustain without the queen. However, there are some ant species (e.g., Platythyrea punctata), in which workers are clonal and lay eggs that develop into females. In these colonies, the most dominant worker will lay eggs while the others maintain the colony. Once this reproductive worker gets weaker or dies, another worker will become the reproductive. A really nice review on exceptional colony structures is "The demise of the standard ant" by Jürgen Heinze.

Coming to your second question: Ants communicate with chemical signals. These can be pheromones or cuticular hydrocarbons. The queen produces a range of pheromones and by this gives instructions to her workers. One important instruction is that the workers don't lay eggs. It is in the queen's interests that she is the only egg-layer and the workers nurse her offspring, forage and defend the colony. So the queen produces pheromones that suppress the ovary development of the workers. Once the queen dies, the workers will start to develop ovaries to lay unfertilized eggs and these will develop into males. Please also read this post on ant pheromones.

All the best,
Steffi Kautz & the AntAsk Team

Specifically, I am asking if there is any record of it occurring. I imagine that the odds of it happening are extremely low, if not zero!

Thank you,
Josh


Hi Josh,

Thank you very much for contacting AntAsk! Actually, this is a really good question. At first glance ant colonies seem to be organized in a standard manner, with one queen per colony. The queen has mated once and she produces workers that are all full sisters. However, when we start taking a closer look at the organization of ant colonies, there seem to be more ant species that have some kind of exceptions than the ones that don't. A really great review on this topic is the paper "The demise of the standard ant" by Jürgen Heinze.

There are some ant species, which don't really have a distinct queen, but special workers that lay eggs and are called "reproductives". One example is Platythyrea punctata. This ant is clonal and theoretically all the workers have the potential to become the reproductive of a colony. In these cases, a single worker could leave the colony and have her own colony. But workers don't leave the colony purposely. It is really risky to found a new colony all on their own and they have a much higher chance of success when they work as a colony. However, if the old reproductive dies, the colonies of these clonal ants can live on. When a workers gets separated by her colony and she is in good health, I suspect, she would try to start her own new colony.

Another case in which ant workers would leave their colony is when they have an infection. Some ants in the tropics might catch an infection by the entomopathogenic fungus Orthocordyceps. A great YouTube video of an infected bullet ant (Paraponera clavata) is found here. At a later stage of the infection, the fungus grows into the brain and alters the infected ant's behavior. The ant leaves the colony, climbs up to the top of a plant and secures itself with its mandibles and dies. Then, fungal fruiting bodies sprout from the dead ants head and explode releasing the spores to infect other ants and complete the fungal life-cycle.

All the best,
Steffi Kautz & the AntAsk Team

Dear Ant Team,
I'm hoping you can help me with my ant query. I live in Sri Lanka, and two days ago, out of the blue, we found 14 ants of the type in the photograph on our bathroom floor. They were extremely sluggish but still alive. Having removed those ants, the next day I found about another 10 on the nearby stairs. These were in a similar state. We recently moved here from Egypt and our shipping arrived last week. We are wondering if something could have travelled in one of the many boxes we have been unpacking of late.
I would be most grateful if you could help me identify them and tell me if I should be worrying about having them in the house. I am concerned I am on the verge of a major ant infestation.
Many thanks,
Caroline


Dear Caroline,
Thanks for your question. The winged ants that you are seeing are reproductives. To learn about ant reproduction check out this post. Unfortunately, it sounds like you may have an ant colony living in your new home, and judging from the picture you sent these ants are probably some kind of carpenter ant in the genus Camponotus. Winged ants are released from their colonies in swarms at certain times of year and if a colony has a nest entrance somewhere inside your house then when they fly out to find mates they will end up in your house. I doubt that you brought that many winged ants along in your shipping. The boxes probably just happened to arrive at the same time that the ants were swarming. These ants may never bother you again but I would suggest you take a look at this post on discouraging ant pests just in case.

Good luck!
Ben Rubin & the AntAsk Team

Dear AntAsk,

I'm designing a behavioral experiment about nest-mate recognition in ants that I hope to publish in an educational journal. When I do the experiment with my class here in Oklahoma, I've been using harvester ants of the species Pogonomyrmex barbatus, but I understand this ant doesn't occur everywhere, and I'd like to offer educators from other areas suggestions for what kinds of ants might work.

Thanks!
Stephanie


Dear Stephanie,

That sounds like a really fun, educational activity! Pogonomyrmex in general are great to use, but here are some other genera that might be useful to people living outside of your region:

Formica spp. (wood ants) These ants are widespread in North America and Eurasia, and are often the most numerous large ants in boreal forests. They build mounds of vegetation (sometimes to 1m high or more) around their nest entrances.

Tetramorium caespitum (pavement ants). The most commonly seen ants on sidewalks in urban North America and Northern Europe. They often have nests with multiple entrances, so get ready to see some non-aggressive behavior, too. Ants truly from a different colony, however, will be violently rejected, and closely-spaced colonies of this species are frequently seen having all-out territorial wars (see previous post here ).

Aphaenogaster sp. and Messor sp. Also referred to has harvester ants, these ants have very similar habits and life-histories to Pogonomyrmex; all three genera co-occur, and are most common from southern California to west Texas.

The majority of ant species show some degree of internidal (between-nest) aggression, so most ants are worth a shot, with the following exceptions: most invasive ants. The Red Imported Fire Ant, Solenopsis invicta, is common and obvious from Texas to Florida. These will often not show aggression to other members of its species. The Argentine Ant, Linepithema humile, is very common in South and Central California; these ants rarely show aggression towards each other in their introduced range (there is actually a "mega-colony" that occurs in Japan, California, and the Mediterranean region in Europe; you can read more here ). Both ant species are originally from temperate South America, where they actually do often show internidal aggression. Many invasive ant species form polydomous and polygynous (multi-nest and multi-queen) colonies and show little internidal aggression in their introduced range, but have more "normal" nest structure, queen number, and levels of internidal aggression in their home ranges.

I did not really address how to identify these ant genera in this blog post, other than to direct you to some pictures. For an entry-level guide to identifying many of the relevant genera discussed above, please see this key, developed for the Bay Area Ant Survey.

For more in-depth information on ant identification, I would highly recommend checking out "The Ants of North America" by Brian Fisher and Stefan Cover.

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

Hi guys!
My name's Mark from the Philippines. I hope you don't mind several questions that aren't necessarily related. :)

1.) I noticed most ants are either black or red. Sure there are whitish ants and some colorful Polyrachis ants but they're minorities. By black I mean dark brown to shiny black and by red I mean the many variations(reddish orange, orangeish, brown reddish etc). What's so special about the two colors? I'm guessing ants' ancestors happen to be black and red wasps and since ants don't need color change to adapt they retained their colors but what do I know. :)

2.) What's up with the way leafcutters look? Atta, Proatta, Acromyrmex etc have this thorny bodies that doesn't make sense to me. What's so special about leafcutting and fungus-growing that they need to evolve with spiked bodies? And also Polyrachis. They have this few large spikes that doesn't seem to have any significance other than birds or lizards might get pricked if they try to eat them and aesthetic purposes.

3.) I found these colony of what seems to be Crematogasters basing on their "heart-butts". They've occupied an abandoned termite nest and when I breached the walls, out came big-headed blockers. So far I haven't heard of trimorphic Crematogasters but the ones I found are, so any idea what species this might be? And also I find it weird how they have these termite style defense when others ants seem to find them distasteful. I dropped one at Pheidoles, Tetramoriums, Solenopsis, Tapinoma and Pharoah ants and they were left untouched. Even dead ones weren't scavenged. Pheidologetons might be their enemies? If so, can you tell stories about them raiding Crematogasters?

4.) I noticed these odd behavior in Pharaoh ants. A medium sized worker seems to be biting a larger worker on the neck. There wasn't any obvious signs of distress on both ants. I first guessed it was grooming but they looked totally stiff which doesn't look like grooming to me. When I disturbed them with my fingers, they appeared confused but that's obviously by the huge thing that touched them. Then they just went of with their marching nestmates. I saw 2 of these weird happening from the same colony, simultaneosly and a few inches apart. Both pairs where a median "biting" a major. Any idea what that was?

5.) I witnessed these funny grasshopper kicking garden ants. At first it was facing incoming ants and then turned around to kick them a few inches away. The ants landed exactly on another of the ants' lines which made even funnier. Is these a unique grasshopper or do many grasshoppers do these?

Thats all! Thanks!
Mark


Dear Mark,

Wow, that's a lot of questions! We'll try our best to answer them, but for most of these, we'll just be giving our best guesses, because without more information, we don't know.

1) So your first question sounds like you're asking "Why aren't ants more colorful?" But then you go on to list all the different colors that ants can be! The different shades of red, yellow, brown, and black that most ants come in are special because these are called pigment colors. They are the most common chemical-based colors in all groups of animals. Human hair, for example, is basically all the colors an ant can be. The colors ants and mammals usually aren't are the structural colors that are so flashy and beautiful in many birds, beetles, butterflies, and dragonflies (check out this website about birds for more information about the different kinds of colors animals use). The few ants that are colors that mammals usually aren't use structural colors (there are green ants and blue-ish purple-ish ants). Part of the reason ants aren't as colorful as butterflies or dragonflies is that they don't rely on visual cues for mate recognition or for sister-recognition. Instead they rely almost entirely on touch and smell. Ants aren't usually as colorful as orchid bees or velvet ants because they don't rely on aposematic, or warning coloration, to warn predators that they are dangerous. In fact, the ant body type and their habit of working together in large groups is distinctive enough that many arthropods have adapted to look like ants - they don't need to be bright orange and white to be intimidating because ants are notorious enough as it is. (see previous posts here and here on myrmecomorphy ). As you observed, ants still come in an impressive array of hues; all the pigment colors found in most other organisms are found in ants. Blues, greens, and bright whites are usually absent in ants because they don't need them for recognition, communication, or for warnings.

2) Again, you've pretty much answered your own question here. Lizards and amphibians are some of ants' most significant predators, and anything ants can do to make themselves less easy to eat would be an advantage. Something you might notice is that none of the ants that are very prickly have serious stings. There are trade-offs involved in how much energy you devote to different kinds of defenses: spines take a lot of extra nutrients to produce, just like venom. Some ants avoid predation by being fast, like members of the genera Anoplolepis and Paratrechina. Leaf-cutter ants in the genera Atta and Acromyrmex are some of the most conspicuous ants in the Neotropics. They can't run away from lizards while they're carrying those huge chunks of leaves, so they've devoted a lot of energy to being prickly and crunchy.

3) We don't know of any dimorphic Crematogaster. A genus that is often found in termitaria that is conspicuously dimorphic is Metapone. This genus is known from the Philippines, but little is known about its natural history. The observations you've made may be new to science! It's important to keep voucher collections of the ants you find and conduct behavioral experiments on, so they can be positively identified. There are more than 80 genera known from the Philippines, but this number is expected to grow with more collections. If you have pictures of these ants, send them our way, and we can try to identify them! Or at least check out the Ants of the Philippines on AntWeb, and Ants of Borneo.

Your experiments on whether or not the other ants wanted to eat your "Crematogaster" might be more meaningful if you conducted them using a delicious positive control. Perhaps the other ants had no appetite because they were afraid of you! If you offered the ants multiple kinds of food at the same time (sometimes called a cafeteria experiment ), then you'd know that at least they were in the mood to eat something.

4) How closely did you look at the Pharaoh ants? It could be that the "majors" were actually wingless reproductive females. In larger Pharaoh ant colonies, there are often multiple queens, and sometimes they assist in foraging (which is part of why they are so easily spread by humans--if a queen happens to be foraging in your lunch box when you pick it up and take it home, you've just started a new Pharaoh ant colony!). The true workers will still take it upon themselves to carry the queens around sometimes, though. We don't understand exactly why they do this, but it could be a relict from when they used to be monogynous.

5) That's really funny. Very little is known about insect behavior in the tropics. Most larger insects will try to flick ants away from themselves if they are being harassed. But wouldn't that be cool if they could flick them into another angry line of ants? If you could demonstrate this by doing statistics on how likely an ant was to be flicked by a grasshopper into another ant line vs. just anywhere, that would be a great scientific paper!

Sorry we can't give you more definite answers to many of these questions, Mark. But if people like you keep making great observations like these in different areas in the tropics, maybe someday we'll know for sure!

Best,
Jesse Czekanski-Moir, Noel Tawatao, & the AntAsk Team

My students and I explored how an ant would react to various ink lines (ball point pen and permanent marker). What we observed was the ant's behavior was not effected by the ball point pen lines, but it would veer away from the permanent marker lines at first....then cross the permanent marker line after a second or two. Can you shed any light on why the ant seemed repelled by the permanent marker line at first, and then why it seemed unaware of the same line later? (Tracey)


Hi Tracey!

Thank you very much for contacting us at AntAsk! It sounds like you are designing really cool and interesting projects with your students!

Two explanations for the behavior you and your students have observed are possible: (i) Ants could perceive the smell or (ii) the color of the markers. If ants perceived the smell, it could then fade after a few minutes (like when you paint a room and after a few days the smell has faded) or the ants could just get used to it. The other explanation could be that the ants react to the color, but then get used to seeing the line. But since you tested a ball point pen line as well and the ants did not react to that, I would guess that the smell is what deters them. To test that you could try several different types of pens (with different smells, in an ideal case you would have a pen that does not emit any smells) and to exclude the effect of color you could use a clear pen or a pen that has exactly the same color as the surface. If the ants react to a pen that is not visible, then it is more likely that the smell affects them. However, different ant species could perceive colors in different ways than humans. In a previous post we answered several questions on ants' senses and this post might provide interesting information for you when designing your experiments.

All the best,
Steffi Kautz & the AntAsk Team

Hi, my name is Tiffany and I would appreciate it if you could answer a few questions for me. A friend and I are doing a project on the taste preferences of ants, and I would like to ask you a few questions regarding these little insects.

My first question is: I found online that ants cannot see the color red. I am trying to hypothesize what sorts of food ants will gravitate towards the most often. Would their inability to see red have any affect on which food they will pick? Do they operate mainly by smell?

My 2nd question is in regards to what attracts ants. Do they like their substances more natural (sugar) or do they prefer something a little more chemical (high fructose corn syrup)? Is there any flavor you know of that is their favorite?

Also, what is your degree in and where did you study? How long have you been working in this field?

Our idea is to buy an ant farm, (and some ants) and, throughout the course of a week, put in tiny portions of different foods (varying in saltiness, sweetness, etc.), record their prefernces, and base our inferences off of these observations. Do you have any suggestions that would help this project become more scientific or more efficiently conducted? Does this idea sound reasonable?


Dear Tiffany,

Thanks for contacting us at AntAsk! It sounds like you are designing an interesting project and you have some great ideas to evaluate the food preference of ants.

We have a detailed post on the senses of ants here and you are correct, ants navigate mainly through the sense of smell. If a food item emits a smell, ants will be able to recognize it from the distance. However, if a food item does not emit a smell (like regular household sugar), ants will touch it with their antennae, where the chemoreceptors are located, to smell or taste it.

To answer your second question: it depends a bit on the ant species. We have written a post on how to bait argentine ants here. My guess would be that ants prefer sucrose over high fructose corn syrup. But this would definitely be a nice question to test in an experiment. You could offer both, sugar solution and high fructose corn syrup simultaneously to your ants and then count the ants that attend the different solutions after 5 min and after 10 min. Ants are usually attracted to sugary solutions (adult workers often cannot swallow other than liquid food, so you should desolve the sugar in water). What researchers often find is that the ants like the sugar solutions the more sugar it contains. So you could offer sugar solutions at different concentrations (e.g., just water (= 0% to serve as control), 10%, 20%, and 30%) to the ants and see what they like best. The research group around Professor Mike Kaspari has found that ants really like salt. So you could try offering salt at different concentrations (e.g., just water (= 0% to serve as control), 0.1%, 0.5%, and 1%) to ants and see what they prefer. You could set-up your experiment in a way that you offer 4 concentrations of either sugar or salt solution simultaneously to your ants and then count the ants that attend the different solutions after 5 min and after 10 min. In one of my papers, I studied the preference of acacia-ants for different sugar solutions. You can find the paper here if you want to read on how I conducted my experiments.

To answer your third question: We are a group of myrmecologists (people that study ants) that was originally based in lab of Corrie Moreau located at the Field Museum of Natural History in Chicago. You can find our CVs on this website (www.moreaulab.org). One of us, Jesse, is now a Ph.D. student in the lab of Mike Kaspari.

Good luck with your experiments and let us know if you have any additional questions!

Steffi Kautz & the AntAsk Team

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