November 2010 Archives

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

Hello,
I have a question about a type of ant we have here in south Texas. Here in Hebbronville we have an ant that sound very much like the Paraponera ant. The ant has a VERY painful sting and it is large and black. The sting is much more painful than that of our native gold scorpions. just wondering what type of ant this may be. They live at the base of older Mesquite trees and my grandparents use to call them "palmoranas" thats a Spanish word for these ants.

Thank you,
Daniel


Dear Daniel,

There are over 140 species of ants known from Texas. You can see a list of the species and images of most of them here.

Without seeing the ant it is hard to be sure what species you are encountering, but I can tell you it is not Paraponera clavata since this ant is not found that far north. You can see a map of the known distribution here.

The ant with the painful sting is likely a species of Pachycondyla if they mostly forage on the ground. These ants are know to be aggressive and have painful stings when disturbed. On the other hand if the ants run up and down the mesquite tree then they could be a species of Pseudomyrmex, which can also have painful stings.

I hope you continue to observe all the diverse and beautiful ants around you!

Corrie Moreau & the AntAsk Team

Fire ants in our area often form lines of mounds along a street curb. Today I noticed a different pattern. This pattern consisted of a dozen, or more, fire ant mounds spaced in a more-or-less equidistant distribution in a large mowed lawn. Space between mounds averaged about 20 feet. I assume that these mounds represent separate colonies? How does one account for the spacing? It does not appear to be random. Is there some mechanism by which some ants from a colony move to a new location in response to some stimulus? Is the adaptive advantage of this dispersal pattern related to food abundance? What initiates sub-colony movement: new queen, reduction in available food, some scent left by ants that builds up as they exploit a site? Have there been studies of fire ant behavior in relation to the resource base? If my observation is accurate, this behavior should maximize efficiency of resource use.

Vincent


Hi Vincent,

Your observation of regular spacing among fire ant colonies is astute and similar to patterns you will see in lawns, pastures, and roadsides across the southeastern US, Texas, California, eastern Australia, and now parts of China. This natural patterning is a characteristic of dense monogyne (single queen form) fire ant populations. Each mound is the home of an individual colony with one queen. The space between colonies is "territory" which is divided up among adjacent colonies, usually in a rank order, where the largest colonies (which often have the largest mounds, too) occupy the largest territories.

Fire ants, especially the red imported fire ant, Solenopsis invicta, are one of the relatively few ant species that maintain absolute territories; that is, they guard and defend an area around the colony (mound), not just the mound itself, from any and all threats. Most other ant species defend only the nest, foraging trails, and food resources, so fire ants are a little unusual because of the amount of effort they put into maintaining their territories. Defense of a territory is probably an evolved response to intraspecific competitive pressure, that is, the fact that neighboring fire ant colonies are really good at competing with one another. The safest way to prevent having all of your food eaten or, more likely, your whole family captured and killed by neighboring fire ant colonies is to maintain a territory, remaining vigilant and defensive to any intrusion into the territory.

Maintenance of the colony boundaries is dependent largely on the interactions among a small number of individuals that scout around the boundaries of the territories. They respond to contact with non-nestmate ants by running away (in small numbers or as individuals, fire ant workers are actually rather timid when away from the nest). Thus, in zones of frequent contact at the edge of territories there actually exists a "no ants land" where there are very few individuals because they are "repelled" from one another by regular contact with non-nestmates. If they do not encounter ants from neighboring colonies they will, collectively, forage further and further from their territory. This thermostatic "control" of colony boundaries ensures that if, say, a neighbor colony suddenly dies, then its territory will rapidly be subsumed into one or more neighboring colonies' territory. As you can imagine, this kind of territoriality requires a large number of workers to maintain.

To the best of our knowledge, fire ant colonies generally do not appear to be resource limited or pathogen/parasite limited to the extent that it would drive frequent colony movements across populations. Fire ants, like most ants, are omnivorous and will opportunistically feed upon a wide range of food items. Colonies may, however, frequently be protein limited, but this does not appear to reach starvation levels that prompt a "move or die" scenario resulting from the resource base within the territory being completely depleted. Nevertheless, fire ant diet is an active area of research, as is territory maintenance. The best, and most complete work on fire ant territoriality has been carried out by my good friend Dr. Walter Tschinkel at Florida State University. Google him sometime and take a look at some of his papers or his book, The Fire Ants, if you would like to learn more!

Joshua King (guest expert) & the AntAsk Team