Hey buddy, can you lend me a jaw?

ant transport

What’s an ant to do when it finds a food item that is too large to carry back to the nest?

Army ants, which forage in groups, will form teams that cart the food item back. Workers of other species will just start dragging the large food item until other workers stumble across the scene and pitch in to help. Or, they may break off a bit of the food, carry it to the nest, return for another piece, and continue that way until help arrives or they’ve finished the job.

Pachycondyla chinensis ants have a different solution. If a P. chinensis worker locates something too big for one ant to deal with, it goes off to find a nestmate — and carries that second ant in its jaws as it returns to the food. Once deposited at the food site, the second ant joins the first in dismantling the item and bringing it back to the nest. Interestingly, the ant being carried remains “totally passive” while in transit.

Researcher Benoit Guenard of North Carolina State University noticed this behavior while observing foraging habits of P. chinensis.

To find out more about how the ants decided whether or not they required help, Mr Guenard placed dead cockroaches in two boxes, or “foraging cells”, close to the nest. One of the cells contained lots of small cockroaches that could be carried individually and the other contained one very large cockroach.

“They quickly learned to bring another worker to the cell that contained the large cockroach,” explained Mr Guenard. “But then we tricked them by switching the cells around.”

Within five minutes, the ants had learned to carry another ant to the correct cell.

This is cool. It also boggles my brain a bit, as I think about how this behavior is encoded. Somewhere in the DNA of P. chinensis, there is a series of instructions that goes something like this:

IF food item is way too big

THEN go find buddy, grab her and bring her back in my jaws


IF buddy grabs me in her jaws

THEN remain perfectly still until I am released at food site

According to Guenard, this buddy-recruiting behavior is something new in the ant research world, unique to this species (that we know of). And that’s precisely why biology is so much fun. Even now, in the age of instant information, it’s still possible to go outside, crawl around on your hands and knees while watching some ants, and learn something completely new to science.

Photo of tandem foraging ants by Benoit Guenard.

About Fletcher DeLancey

Socialist heathen and Mac-using author of the Chronicles of Alsea, who enjoys pondering science, politics, well-honed satire (though sarcastic humor can work, too) and all things geeky.
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5 Responses to Hey buddy, can you lend me a jaw?

  1. Inge says:

    lol. Do you think they have to proof they can carry their weight around by actually lifting the other one? Seriously, i mean, why would they carry them and not just take their hand and guide them along, so to speak?

  2. Malkor says:

    Another case of the “genetic memory” theory in action. I believe this theory to be a fact, and am also a fan of it. Those ants above seem to be a pretty good example of inherited or hardwired “thinking”.

    I am also convinced that all species are born with all the knowlege they need to survive.It is probably the reason for widespread arachnophobia. I myself have experienced my hair raise when insects with the ominous yellow/black warning-colours get too close, which indicates that genetic memory also works with modern humans. Sadly certain patterns of behaviour also seem to be handed down in a bloodline over a, historically seen, shorter period.

  3. MJ Valente says:

    Wow. I had a vision of a caveman carrying a mate: “Uga, buga. Eh, bro’, gonna help me carry food to nest. NOW!”


  4. Ana_ñ says:

    I think I have demonstrated for many months how much I like your science posts. Well, with all due respect, I don’t like this one at all; in fact, I hate it. The reason: I’ve being feeling like the main character of a bad horror movie. I’ll spare the details; suffice to say that it was about a sweet plumber, a nest of possessed cockroaches* and pesticide poisoning. Still a bit dizzy, I’m recovered enough to resume slowly my habit of sending silly comments, like this one, to your blog. 🙂

    *They would fall in the “very large” category of the foraging cells (and with wings)

    • oregon expat says:

      Don’t tell my wife! Cockroaches of any type, but especially the winged ones, send her right off the edge. This is a woman who can boil animal bones for analysis without blinking an eye, but one glimpse of a cockroach and off she goes. You have my total sympathy (esp. for the pesticide poisoning — yikes!).

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