February 2012 Archives

Bas--

After a couple responses from two of our African ant experts--James Trager & Peter Hawke--we have confirmed that the ants from your picture are the savannah form of the southern African ant Camponotus fulvopilosus. One of our experts believes this could be an example of their known behavior of "tandem running". Unfortunately, there are no pictures on AntWeb currently, but one of our experts mentioned that he has some queued up for imaging, and thus will be up on the site sometime this year.

As an aside, the species is very aggressive, and the majors can inflict a painful bite! Apparently, their sting contains a 45% solution of formic acid, and have a tendency to do so after running up your legs! Beware!

Thanks for your question!

Max Winston & the AntAsk Team

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Last year I was in Namibia and near the Waterberg plateau I've seen these giant ants marching. Can anybody help me with identification? I don't have a clue. If suggestions could be mailed to b.brinkhof@uu.nl I would be very grateful,

Bas Brinkhof
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Hi, I have an Atta sexdens Queen and I wanted to know how can I control her fungus to not overrun the space so early? I heard that this type of leafcutter-ant grows very very fast, and if there is anyway to retard this fast process..

Giving small quantities of plants would solve this problem? Or there is another way to do it? And here I sent some pictures of my colony :)

Thank You
Best Regards,
Felipe

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Dear Felipe,

To answer your question, we contacted Randy Morgan, who is an expert on keeping live ant colonies and Curator of Invertebrates, Reptiles and Amphibians at the Cincinnati Zoo & Botanical Garden, and here is what he had to say:

"Congratulations for successfully collecting a young leaf cutting ant (Atta sexdens) colony! Your little colony (containing a mated queen, perhaps 50-100 workers and small fungus garden) is now about one year old and so far has been growing relatively slowly. You are correct, established colonies can grow very quickly. Your colony is just entering the stage of rapid colony growth and in several years could contain 5-8 million workers and hundreds of melon-sized fungus gardens!

Obviously keeping a fully-grown colony in captivity would be next to impossible. Even so, many universities and insect zoos keep partially-grown colonies for research and/or public educational display, and these colonies are often hardy and long-lived. However, one year old colonies are relatively fragile since fewer workers are available to help maintain an optimal nest environment (100% RH; 25-27º C) for fungal growth. Environmental stress, especially even slightly lower atmospheric humidity, can lead to garden decline and eventual colony collapse. Thus, it would be ideal to grow your colony at least somewhat larger (i.e., minimally several thousand workers and two large fungus gardens) and to do so as quickly as possible. Experience has shown that it is better to keep small colonies growing rapidly and then culling excess workers and fungus from time to time, rather than limiting plant matter (the latter essentially starves the fungus and makes it less productive and poorer food for the ants). Before you drop excess fungus gardens with attendant workers into the freezer, break apart and sort through the gardens to ensure that the queen is not present!

Maintaining observation nests for Atta can provide an endless source of educational fun. To be successful long term, one should become knowledgeable about the ants' sophisticated social organization and intimate association with their fungus gardens and other resident micro-organisms. It can also be helpful to think of yourself as the "Assistant Fungus Gardener" with your primary job to do whatever is necessary to help the ants maintain a nest environment conducive to fungal growth. If the fungus thrives so will its ant colony.

Please find a document summarizing Atta biology and one husbandry system that has proven to be effective here: Leaf cutting ants-IECC 08.pdf. Of course other culturing techniques may also work as long as the needs of the fungus come first. Good luck, thanks for writing and please keep us posted on how your work with Atta is progressing.

Randy Morgan, Corrie Moreau & AskAnt Team



Dear AntAsk:

I have found several of these creatures that sort of look like ants, but I don't believe they are. DSC_0473.jpg
I live in mid Michigan. I do have firewood in the room where they were found. The bugs don't seem to have very big mandibles compared to their size of 1cm. They have distinctive markings on their backs. Do you have any idea what they might be?

Jim
Wacousta, Michigan


Hello Jim:

Sorry to take a few days to get back to you on this. I had to consult with a beetle expert colleague to make sure I was giving you the right information in this reply. Here's what he wrote: "They are cerambycid beetles - the first (0472 and 0473) are Cyrtophorus verrucosus, and the last (0474) is Euderces picipes. Yes, they are both ant-mimics (and a nice example of convergence as they are not particularly closely related to each other)." I would add that both of these beetles mature in dead wood, and no doubt were stimulated to emerge by the warmth inside your house.

We get quite a few inquiries about other critters that look more or less like ants. Some of these might be considered true ant mimics (other animals that look more definitely ant-like in appearance and outward behavior than other members of their respective taxonomic families), and others are not especially ant-like, but are perceived as such by folks having little experience with insects, generally. Here are a couple of relevant posts:
http://www.antweb.org/antblog/2010/07/if-it-looks-like-an-ant.html

http://www.antweb.org/antblog/2010/09/are-these-ants-torie-charleston-sc-usa.html

James C. Trager of the AntAsk Team


Some great questions about ants were submitted to the AskAnt Team by student Jinho Lee from California. Here they are, with replies:
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If ants were not historically small, at which point in civilization were they larger?

The first thing I would mention is that the "history" of ants is much longer (over a thousand times longer!) than that of humans. In other words, the whole history of human civilization is just a "blink of an eye" relative to ant history, so it doesn't really make sense to ask "at which point in (human) civilization?". The first ants are believed to have originated between 130- to 150-million years ago. The oldest known ant fossils are dated at about 110-million. Ant fossils are generally in the same size range as most modern ants. But, note that modern ants range greatly in size, from barely over 1 millimeter (mm.) to over 30 mm. in length. There are a few fossil ants even bigger than this, but these are relatively recent, and not ancestral, "only" about 30-million years old.

Can ants see shapes and colors?

The visual abilities of ants vary widely. Large-eyed ants such as Gigantiops & Pseudomyrmex perceive movement and shape well, but their color perception has not been carefully investigated. It is generally believed, but not well documented, that ants with good vision probably have about the same spectrum of color sensitivity as honeybees, i.e., they see ultraviolet, but not red. Many ants, such as small Acropyga & Hypoponera species have poorly developed eyes, and do not perceive visual images, only light, dark, and possibly motion.

What type of bug did the ant descend from?

Ants and wasps both belong to the insect order Hymenoptera (wasps, bees, sawflies and relatives) and all are descended from a common wasp-like ancestor. Based on the predominant appearance of fossil and modern Hymenoptera, it seems likely the common ancestor was more like what we would think of as a wasp than an ant.

What age are ants when they first start to contribute to the colony?

Probably the better way to ask this would be "at what stage do they start to contribute?". In one sense, they start young, as larvae, because adult ants have a very narrow esophagus and cannot eat solid food, while larvae have a larger gullet and can swallow and digest chunks of food. Many ant larvae regurgitate predigested or pre-chewed food to the workers (sort of like a mother bird feeding its young, in reverse), thus contributing to colony nutrition. As soon as ants reach the adult (typical ant) stage, they begin colony work - taking care of the young, cleaning and building the nest, and eventually foraging and defending the nest.

In your opinion, do you think that an ant colony that lives in the ground is more likely to survive than ants that live in a tree or ground level?

It depends -- Different species of ants have habits and body adaptations that help them survive in particular habitats. An arboreal ant species survives best up in the trees, but a blind, subterranean ant species would shortly die if it tried to survive up in a tree. A large variety of ant species have been successful in both environments (but different ones in each) .

How can ants tell the difference between intruder ants and ants in their own colony?

Ants have a keen sense of smell, and (like our much better known pets, dogs) can recognize individual and colony (family) odors that help them distinguish nestmates from outsiders.

Explain "aphid" and "myrmecophilous".

Aphids are plant-sap-feeding insects that have a peculiar problem; They have so much sugar in their diet that they excrete sugar water as a waste product. Many ants like sugar as an energy source, so they gather and drink this aphid "sugar-urine" (properly called honeydew) from the aphids (or from related insects with similar secretions, such as scale insects and mealy bugs). Some aphids, etc. even live inside ant nests under ground, and are moved around by the ants to fresh roots, to drink sap and make the sugary waste product for the host ants. The ants even take care of the aphids' eggs. These kinds of aphids are described as "myrmecophilous" (Greek for ant-loving).
Many other sorts of insects, mites, spiders and millipedes may be found in ant nests. When the ants' nests are the are primary habitat of these other insects, these ant "house guests" are called myrmecophiles.



Dear AntAsk,

Last night my brother was stung by something that looked a lot like the Myrmecia piliventris. I didn't take a picture (I was too busy trying to kill it), but I found Alex Wild's photo on the internet, and the thing that bit my brother looked a lot like it.
I read on Wikipedia that these ants are mostly found in Australia, and since we live in Namibia, I was wondering what it could be? Any idea?

Thanks!
Corien


Dear Corien,

Next time, kill the ant more carefully! (or better yet, photograph it alive, like Alex Wild would). Without specific information about which parts of the ant reminded you of Myrmecia, it's hard to say what species it was. One thing I'm fairly certain of is that it is not Myrmecia piliventris. Unless you or one of your neighbors just came back from a trip to Australia, it's pretty unlikely that genus would show up anywhere outside of Australia, or the islands immediately next to it (Myrmecia is also native to New Caledonia). Members that genus have been reported by New Zealand quarantine officers, though, so it's not impossible that commerce will one day introduce a "bulldog" ant to some place beyond the land down under.

I'd say your best bet is to check our Ants of Kenya page. It's still not exactly Namibia, but the genera at least are much more likely to occur in both Kenya and Namibia than Australia and Namibia.

If it was the mouthparts (mandibles) of Myrmecia that reminded you of the ant that stung your brother, then some possibilities that leap to mind are the genera Leptogenys and Plectroctena. Plectroctena can grow quite large (with a headwidth of 4mm). Leptogenys are generally smaller, and look as if they are probably faster. Although they do have pretty noticeable stings, it would have been difficult to see the mandibles on most Leptogenys species I'm aware of without using a microscope, so I doubt it's that one.

Another noteworthy trait that Myrmecia has are their large eyes. In Africa, Asia, and Australia, the ants with some of the largest eyes relative to their head sizes belong to the genus Tetraponera. These ants (and their relatives in the Americas, Pseudomyrmex) have some of the largest eyes in the ant family, and their elongate bodies are similar in shape to the bodies of Myrmecia. While some Tetraponera can grow quite large and be rather aggressive, like the Southeast Asian Tetraponera rufonigra, I can't find evidence that there is a Tetraponera that big in West Africa.

In many parts of the world, especially in the tropics, if a medium-large ant has just painfully stung you, there's a good chance it belongs to the genera Pachycondyla or Odontomachus. These don't bear a specific resemblance to Myrmecia (Odontomachus does have elongate mandibles, but they are attached near the midline of their faces, rather than at the corners as in Myrmecia, Plectroctena, and Leptogenys), but they might be more common in some places than other genera mentioned in this post.

Good luck! Feel free to send us pictures if you see an ant like that again!
best,
Jesse Czekanski-Moir & the AntAsk Team

Dear Ant Ask,

I am 10 years old and doing a science experiment using ants. I want to find the best repellent that is planet friendly and won't kill the ants. I got some harvester ants that I have set up in a jar with sand, food and water. I got an ant farm but didn't put them in because I would not be able to get them out easily. My idea was to make 6 inch circles on construction paper. On the perimeters of each circle I would try a different kind of natural repellent such as chalk, cinnamon, catnip, mint oil. The first trial, I marked out the circle with just marker. As bait, I placed a drop of jam 3 inches outside the circle. Put 3 ants inside circle and they began to run around freely but had no interest in the jam. Tried a circle with an insecticide repellent. Ants still ran around freely, didn't care about jam. I also tried a ring of chalk, same results. Not the right bait? Bad set up? Ants to nervous? I am thinking I need to set up a habitat that they are comfortable in that I could easily manipulate. Can you help me? Any thoughts? Maybe a maze? How could I set up this experiment to show the best natural repellent without killing the ants? I really want to put them in my ant farm when I am done.

Thanks, Luke

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Dear Luke,

Your idea for a science experiment sounds fun and informative!

I agree that getting your ants to feel more "comfortable" before you start the experiments is a great idea. I know you have an ant farm to move them into once you are finished with the experiments, but since you need to be able to observe them and change the repellents I would suggest moving them into a large container with a tight sealing lid (maybe like the "simple Tubberware model" found in this post). Once you have moved your ants into a temporary home with enough space for you to introduce your experimental circles of construction paper, I would wait a day or so for them to get used to the new space. Be sure to provide them with water on a moist cotton ball.

Once you start your experiments you should be sure to use a scientific "control" to insure that the ants are not deterred by the construction paper itself. To do this you will create a circle with jam, but no repellents to see if the ants are attracted to the jelly. You could also try a cotton ball soaked in sugar or honey water.

Also this post here has lots of useful information that may help with your experiments.

Best of luck and enjoy your ants after your experiments!
Corrie Moreau & the AntAsk Team

Random insect found in fireplace
Columbus Ohio
Wings as long as body
Unusual dorsal spike shield like area
Never seen one before

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Dear Josh,

Here at AntBlog we get lots of questions about ants (surprise) and sometimes other insects and spiders that mimic ants which we love, but it is nice to get questions about other bugs from time to time. Thanks for sending in the photo of the very cool insect you recently found. This certainly helps with identification.

What you have is a wheel bug (see a beautiful photograph of a wheel bug by Alex Wild here).

Wheel bugs (Arilus cristatus) are predatory insects found in the eastern United States. Since these insects prey on other soft bodied insects including many pest species they are considered beneficial. They are easy to identify from the wheel shaped structure found on their thorax (although I have often thought this structure looks more like a cog from a machine than a wheel).

You can read more about them here and here.

Enjoy your great find!
Corrie Moreau & the AntAsk Team

Thristy ants


Hi AntAsk,

I am in seventh grade and i'm doing a science project on ants. I'm studying a colony of Linetithema humile, and I was curious, if, and when, ants drink water.

Thanks,
Dominica

Hello Dominica:

Ants, like other living organisms, are mostly water. In general, ants from desert climates are a little better at avoiding water loss than are those from more humid or cooler climates, but interestingly they do this mostly by behavioral means, such as foraging at night or only during the coolest hours of the day, or climbing above ground level on stems or pebbles periodically to avoid the heated ground surface. And of course, they drink water when they encounter it. Adult ants consume an almost exclusively liquid diet, so they do acquire a lot of water from their diet, but like any other animal, when the water content of their body fluid is low, they experience thirst, and drink water from dew, droplets in moist soil or sand, or the lawn sprinklers.

Indeed, it is landscape irrigation that allows Linepithema humile to survive in California and the Mediterranean Region of Europe, where the climate is too dry for these ants, originally from humid, subtropical Argentina and Paraguay.

James C. Trager and the AntAsk Team