Adventures Among Ants - Mark W. Moffett [28]
To a military historian, the marauder ant strategy evinces a classic use of personnel. Placing large numbers of abundant and expendable weak individuals in jeopardy at the front lines not only increases the catch but also minimizes the loss to the society overall. The Romans used a similar strategy at their battlefronts: instead of drawing from highly trained city dwellers, they largely conscripted farmers, who were available in droves and could be replaced at little social cost—a practice that continued at least into medieval times, when poorly trained men were, literally, used as cannon fodder.7
The minors’ bold actions assure few large warriors being sacrificed, a sensible outcome given the expense of raising majors that can weigh hundreds of times as much as one minor. In a sense, the medias and majors are equivalent to the human warrior elite—physically stronger, superior fighters, often positioned behind the relatively inefficient front-line rabble. The human elite are provided with better weapons and training and protected by the most expensive armor, as tough as a soldier ant’s exoskeleton.
The large workers are attracted to a prey’s flailing extremities and dutifully hack off every moving leg and antenna. With the prey rendered powerless, unless its shape is awkward (like that of a praying mantis, which the ants will tear apart), the minors heft its body back in one piece. I once saw the ants retrieving a limbless gecko, which clued me in that they had taken it alive.
Dismemberment immobilizes but doesn’t necessarily kill. Moving animal prey to the safety of the nest before the coup de grâce may reduce the chance of its being stolen by competitors or washed away in a storm. By keeping prey alive, the ants may also be able to preserve their meat (something that ants with stingers do by paralyzing their victims).8 I learned of this strategy one day at the Botanic Gardens when I snatched a limbless katydid from marauders on the way to their nest. I put it in a jar and forgot about it until, two days later, I noticed its leg stubs still writhing. That night I dreamed I was that katydid, being helplessly transported to the bowels of the nest, to be digested at the ants’ convenience by the protein-hungry larvae.
SPRINGTAILS
Marauder ants conduct raids to catch tough prey, but mass foraging helps them obtain other kinds of meals as well. The poorly armored minors, though not intimidating, are agile and have good vision. I’ve watched hundreds of them retrieve speck-sized jumpers called springtails.
Springtails are the rabbits of the insect world—fast breeding, abundant, and prodigiously jumpy. As the name implies, they use their tails as a spring. If one senses a threat, its tail, or furcula, normally folded under the body, snaps downward, launching the insect through the air.
Before exploring the marauder ant’s tactics for capturing these motile creatures, let’s first look at a very different approach. A speck herself, a burnished red Acanthognathus teledectus ant moves stealthily through the forest litter in Costa Rica, her long, pitchfork-shaped mandibles held straight to each side. Coming on a springtail, she slows to a glacial creep until two long hairs extending from her mandibles touch the quarry, indicating that her distance is perfect. Her jaws snap forward; their prong tips puncture the springtail and hold it tight. Quickly now, the ant slings her hind end under her body and incapacitates the prey with an injection of toxins through