I wouldn’t have known they were Pogonomyrmex Barbatus harvester ants if they hadn’t been butchering the caterpillar just as I was slicing carrots, late in the day, for our wild desert cottontail rabbits. Our Cochise County, Arizona, acreage is rife with wildlife. The bunnies love the snacks even though most of their diet remains based on wild greenery. I did know there was a thriving colony of red harvester ants a few yards from where we put out the carrots but had assumed they were Pheidole tepicana, not Pogonomyrmex barbatus. I’ve photographed many a Pheidole ant over the years; the Pogonomyrmex were a surprise.
Not that I realized what they were doing at first. It was just that a couple of feet from my right foot where I squatted, Buck knife in hand, slicing carrots, a bunch of red ants were busy bustling around in one little spot, doing something. I got curious, eyeballed the situation for a while, and finally realized they were cutting up a caterpillar carcass.
The caterpillar had been fairly small one, smooth rather than fuzzy, black with yellow triangular markings on the various segments. I have no idea of the species.
For the caterpillar’s sake, let’s hope it was dead before the ants gang tackled it. Authorities claim this species will “harvest newly dead insects”, but have you ever seen a caterpillar drop dead on the spot for the heck of it? Frankly, I haven’t.
So, did the harvester ants kill or simply scavenge? No clue on that one. Not really. I do know that for a while they were hacking away at the carcass so energetically that they made it move as if it were writhing, struggling on its own, from time to time. However, that–though gruesome–was doubtless an illusion. There were ants jaw-sawing and pulling at both ends, sort of a butcher’s tug of war.
Finally, I observed an ant manage to completely sever a segment of the caterpillar and begin to lug it away toward the nest, well separated from the rest of the remains. Only then did I come to fully understand what they were doing, and why. Hippety hop to the butcher shop, Pogonomyrmex barbatus style.
The segment turned out to be a bit much, though; the ant trying to lug it quickly decided enough was enough and efficiently cut it down to manageable size, taking one chunk but leaving another, either for a return trip or for one of her sisters to gather.
In the meantime, other meat processor ants were still hard at it, carving up the rest of the carcass.
There are a couple dozen more photos in the archive, but how many caterpillar-swarming pics does one need to get the point?
Well…maybe one more. There was another ant–also a Pogonomyrmex variety, I believe, though definitely not barbatus and a much darker color–who approached pretty closely, clearly curious. The red ants paid the visitor no attention, though actual contact would no doubt have been met with a ferocious response.
I noticed some puzzling behavior by that other species the next evening. In two separate spots, half a dozen ants were hanging out in one little area a few inches in diameter while at least one member of the group ran around in seemingly confused circles. No idea what that was about. Didn’t bother to try to photograph it, either; it was after dark, and the camera could only have captured a blur of movement.
Considering how viciously some ant species–honey ants, for one–treat any ant not of their own colony, it’s a treat to watch the harvesters. They appear to coexist peacefully, more intent on gathering seeds (their most frequent activity) or scavenging caterpillars than they are in fighting with their neighbors.