September 2012 Archives

The fate of injured ants



Petar writes us this:

I heard ants can't regenerate - Is that true? Also how much of a healing power do they have? I accidentally squished the gaster of one of my ants and he is still alive. Will it heal?

Dear Petar:

Thank you for your questions about the healing abilities of ants, which I will answer in order:
- Ants, and insects generally, do not regenerate body parts as do crustaceans (crabs, lobsters) and arachnids (spiders, etc.). Even for those animals, regeneration is largely limited to the limbs - legs, antennae, and feelers - and most importantly, is dependent on continued growth. The new structures develop under the old exoskeleton, and emerge the next time the critters shed their "skin". Since ants never molt after reachign the adult (ant) stage of their life, they do not have this ability.
- This does not mean ants are unable to heal from injury. It is fairly common to find ants walking about and behaving quite normally, with missing parts or dented or scarred exoskeletons. It is a safe assumption they were damaged in sustaining these injuries, and then healed from them. We know they can sustain some puncture wounds as well, by healing over the breech into their innards.
- The organs inside the gaster are quite adjustable in position, and can slide past one another to a large degree when the gaster is compressed. As long as those internal organs were not seriously damaged, your ant may heal.

Please note that your ant is not a he (unless it is a winged male), as worker ants are genetically female, and some even may lay eggs under certain conditions.

James C. Trager of the AskAnt Team


Hi there, having been to France recently on a University field course I noticed that there were many aphid guarding/milking ants on Broom bushes. I have a few pictures, I find this interaction fascinating so I'd really like to know what species it is.
If it helps any I was in the Cevennes region of France. I've got pictures, not terribly clear I'm afraid. Do you know of a good Ant ID key on the internet? Even to get it down to Genus level would be most useful.
Thanks,
Lorna

French ants (1) (1).JPG
French ants (2) (1).JPG

Hi Lorna,

Thanks for your interest in these interactions. They really are amazing! We contacted an expert on French ants, Christophe Galkowski, to help answer your question. According to him, "ant-aphid interactions are very common in France, many species are concerned, especially in the genus Lasius." He also identified the ants that you found as belonging to the genus Formica and are most likely Formica (Serviformica) fusca. This key may be useful for identifying other ants you collected while in France.

Thanks for your question,
Christophe Galkowski, Ben Rubin, and the AntAsk Team

I'm thinking about doing a science fair project on ants. I was hoping to create a habitat for two colonies of ants and then connecting them by removing a plastic divider. Wanted to observe what the colonies would do and how it would change their behaviors finding food, etc. Also, I read that certain ants can float by linking together on top of water. Is this true? Will ants from two colonies link to survive?

Marion


Hi Marion,

We have several posts on ant farms here, and particularly this post might be of interest to you.

Almost all ant species will viciously defend their colony against ants from a different colony. This being said, once you remove the plastic divider, the two colonies would fight each other. If the two colonies are from the same species, workers usually fight one-on-one in often lethal fights and the larger colony would win. Check out this post by Alex Wild on territorial fights of pavement ants. If the ants you bring together are from different species, it is hard to predict which one would survive.

ant_battle1.jpg

Two pavement ant colonies fighting (Tetramorium). Photo by Alexander Wild (http://myrmecos.net/2010/09/21/the-battle-for-clinton-lake/).

To answer your second question, fire ants can link together to float. This behavior actually helps this invasive species to survive during floods and to colonize new habitats. (To find out more about fire ants read this post.) Researchers have discovered the mechanisms behind these living floats and found that ants use the buoyancy of air bubbles to float. Linking their bodies together increases water repellent activity. Here is an article on the study by Mlot and colleagues, which was published in 2011 ("Fire-ants self assemble into waterproof floats to survive floods" PNSA 108:7669-7673).

Fire ant.jpg

Air bubbles enable fire ants to float. (Picture is courtesy of Mlot, Tovey and Hu, Ant Laboratory, Georgia Institute of Technology).

I hope this answers your questions!

Steffi Kautz & the AntAsk Team


Hi Ant folk:

I am interested in finding out if ants in the Myrmicinae tribe produce silken cocoons as I am trying to get hold of some samples. Do you know anyone who has Acromyrmex echinator, Atta cephalotes, Pogonomyrmex barbatus or Solenopsis invicta in culture who might have some cocoon samples hanging around (if they exist)?

Thanks for your help.
Cheers, Holly

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Hello Holly:

No ant in the subfamilies Myrmicinae, Pseudomyrmecinae or Dolichoderinae is known to produced larval silk. The adaptive significance of this fact, and the metabolic fate of their silk production genes and anatomy is not well studied (unknown?), though perhaps one of the others on our team may know more.

Mature larvae of most species in the other subfamilies normally do spin a cocoon before pupating, so those are where you'll have to seek the materials in question, I suppose.

Just wondering, how did you arrive at this particular list of species?

Best regards, James C. Trager of the AskAnt Team.

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Hi James,

Very interesting. I came across the list of ants as I have been looking for the silks genes from the genome projects. Our lab has done a bit of work on silks from Formicinae and Myrmeciomorphs in the past and I am looking to add to the dataset.

It's interesting that you say Dolichoderinae also don't produce silk as Argentine ants have also been sequenced. Do Myrmicinae, Pseudomyrmecinae or Dolichoderinae have unique domiciles? Are they weaker than other subfamilies?

Thank you for your response and I look forward to having a few more ant conversations.

Cheers, Holly

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Hello Holly:

Myrmicinae and Dolichoderinae are diverse taxonomically and ecologically, with a wide range of nesting habitats, about which no generalizations may be made. Pseudomyrmecinae are almost all inhabitants of cavities in plants, and interestingly, species in the huge genus of Formicinae called Camponotus vary in cocoon production in a way that may be interesting to you. Soil and dead and rotten wood inhabiting ones typically have pupae in cocoons, while many that inhabit the tight confines of plant stems, notably the subgenus Colobopsis, lack cocoons.

Nonetheless, I rather think that lack of cocoons could be more of a nutritional matter than a matter of where particular ants live. A diet dominated by nectar, honeydew and fruit juice, or by seeds, is low in protein, so perhaps it was adaptive for the mainly nectarivorous or granivorous ancestors of these groups to eliminate silk production in order to conserve amino acids for growth and development. Many Formicinae are evidently more carnivorous than at some of the Dolichoderinae and Myrmicinae, and at least some have nitrogen-fixing, internal bacterial symbionts that could mitigate the nitrogen compound deficiency. I hope that my making this sweeping, and perhaps wrong guess/generalization will stimulate commentary from some others, and perhaps other myrmecologists can be brought into the discussion . . .

Do let us know if you hear from them.

Regards, James C. Trager of the AskAnt Team

Aloha,

We live in Kailua-Kona, HI and have tiny, and I mean tiny, red ants inside of our home recently, and we are unsure what they are looking for, what they like to feed on, and are also wondering how to control them. We keep our kitchen counters spotless, but they are all over the counters, and while watering an indoor plant today, the soil exploded with these ants. Also, after opening the top to our coffee maker this morning, there were hundreds and hundreds of these ants inside, so it seems that they like moisture, maybe for nesting.

Any assistance you may provide would be appreciated.

Mahalo,
Tom
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Dear Tom,

Aloha! We are sorry to hear you are having an ant problem in your home and have contacted an expert on Hawaiian ants, Dr. Paul Krushelnycky, and here is what he had to say:

"Aloha Tom,

As I'm sure you know, keeping your home completely free of ants is difficult in Hawaii. You're already doing one of the most important practices, which is keeping your kitchen clean and reducing sources of attraction. But you're right that often water is the main target, especially during dry periods and in dry areas like Kona, and its hard to do much about that. Your ants are most likely one of two species: Plagiolepis alluaudi (doesn't seem to have a commonly used common name) or the little fire ant, Wasmannia auropunctata. The latter is much more problematic than the former; you've probably already heard a lot about this species in the local media. Its now widespread in the Puna area of the island, but has recently also been detected at several locations on the Kona side.

Normally I'd recommend using a sugar-water based bait, like Terro, to reduce and hopefully eliminate new and/or small infestations. However, while this is probably the best approach for Plagiolepis alluaudi and some other household pest species, if you have an infestation of little fire ants, Wasmannia auropunctata, you'll want to do your best to eradicate them before they get too established in your home and on your property. Otherwise, you'll have to deal with a species that can reach very high densities and inflict constant, irritating stings. While the stings aren't as sharp and immediately painful as the tropical fire ants (Solenopsis geminata) we have in sunny coastal areas, they can cause a persistant painful and/or itching reaction that can last for hours or in some cases days. Some people have stronger reactions than others. If you've already noticed something along these lines, then you may have little fire ants. (A close-up photo of some workers might allow an identification, if in focus). The potted plant you mention could have been the source of introduction - colonies are easily spread this way. Did you recently purchase the plant, and did this roughly coincide with your new ant infestation? If so, eradicating the colony could be as easy as drowning it in the pot, using hot water, if they are indeed nesting in the soil. But if they are nesting in other or multiple locations, you'll need to bait them to get rid of them. If they're already widespread, eradication may be unlikely.

I can address additional questions you might have, but I would also encourage you to visit the website: http://www.littlefireants.com/ Its an excellent resource maintained by Cas Vanderwoude, a specialist on invasive ants who currently works with the state and is based in Hilo (I'm on Oahu). He focuses on little fire ants, and I believe has been trying to deal with some of the Kona sites. His website has a lot of information that can help you determine whether you indeed have little fire ants, general info about this and other species, and most importantly recommendations on how to control them. Cas has been working on developing baits specifically for this species. There is also a google-based email list for discussing little fire ants and invasive ants in Hawaii in general. Instructions for signing up are on the website."

In addition you can see a list of the ants of Hawaii with high-resolution photographs for most species here: http://www.antweb.org/hawaii.jsp

I hope this helps,
Paul Krushelnycky, Corrie Moreau, & the AntAsk Team