Check this out:
Arizona State University biologist Adrian Smith drops a few army ants into an Aphaenogaster harvester ant nest and mayhem ensues. Within seconds, the harvesters mass-evacuate with their queen and all the brood they can grab.
A remarkable aspect of this behavior is its predictability. Almost every colony will bail at the mere scent of an army ant. And it’s not just this species, either. I’ve seen Pheidole, Camponotus, Nylanderia, and other ants react the same way. A complete freak-out is apparently a successful strategy to counter army ant raids, and its ubiquity among target ants testifies to just how much pressure army ants place on the survival of other colonies.
A personal blog by Illinois-based biologist and photographer Alex Wild.
That’s really cool to see. The speed and scope of the reaction is quite telling.
Now I want army ant scent in a spray can.
Neat. Me too!
How about Linepithema? Or do they just point at http://en.wikipedia.org/wiki/Argentine_ant and jeer, “Hey, you guys get any press more recent than `Leiningen Versus the Ants’ yet?”
Did I miss something or were the added ants about 10% the body mass of the others? A half dozen tiny ants caused those harvester ants to freak like that? Wow, I wonder what their mites are like.
That first pour in the video was of about 50 army ant workers. Lamon and Topoff (1981) published a report on evacuation behavior exhibited by several Camponotus species in response to this same army ant species. They describe an even more extreme reaction:
“Camponotus festinatus was unique in that it was the only species to exhibit nest evacuation, and in addition, contact with N. nigrescens by a single forager was sufficient to initiate this response.”
Is this defense mechanism diminished in distant ant species that have likely evolved out-of-contact with the army ants? (perhaps relating to “dear enemy phenomenon”)…
So is this a potential methods for non-destructively determining colony size? Add a few drops of army ant extract and aspirate everything that emerges. Seems like an intriguing idea.
Wow – I’m going to have to learn more about army ants. They must be a serious threat to cause that kind of reaction.
Is there a control ant group, where they don’t freak out? That would make it more believable.
Is someone exploring these ants, or their smell, as an ant repellent? Of course, if everyone on the block was using army ants instead of borax or sprays, the results might not be what was expected, but it would be nice to see lawn freaks stop poisoning their ants.
Not a lawn freak – just want them out of my house! Gimme now!
This experiment is ant terrorism.
[...] video by Adrian Smith showing what happens when an army ant is dropped into a harvester ant colony: Mass Panic! The colony goes from 0 to absolute chaos in a matter of seconds. Alex also has some images of a [...]
[...] Raid fronts concentrate workers into a number of exploratory columns, each with enough ants to bring immediate pressure onto any prey colony they encounter. These dense columns are important because prey aren’t naive. When facing army ants, targeted colonies evacuate quickly! [...]