After my recent photo sessions with Pogonomyrmex occidentalis, I decided that I would go and check on another of the Harvester Ant species that live in Southwestern Colorado – Pogonomyrmex rugosus, the Rough Harvester Ant.
We don’t have Pogonomyrmex rugosus at our house, only Pogonomyrmex occidentalis. We’re at around 6500 feet in elevation, which is too high and cold for P. rugosus. I needed to get to about 5500 feet or lower – so probably down into the canyons.
There was round of Spring storms forecast for the next day, which would probably shut down ant activity for a week. If I wanted to see Pogonomyrmex rugosus, I had to go soon, while the sun was still shining.
So…I packed up the Jeep and drove off on a epic Pogonomyrmex rugosus safari. I could almost here the voice-over: “Stand By…For ADVENTURE!”
I found them almost as soon as I arrived in the lower desert. Their flat, mostly bare nest discs were interspersed with the tall, rounded nest mounds of P. occidentalis.
Their coloration was different than what I’d seen down in Arizona. Most of the Phoenix and Tucson Pogonomyrmex rugosus were concolorous black or brown. These ants had a similar dark bluish/black base color, but they also had a beautiful golden-yellowish cast to their gasters.
As if they had been partially dipped in honey. These were beautiful ants.
I’m not sure how valid subspecies classifications really are, especially with regard to ants, but I imagine these are the ants that my older books call Pogonomyrmex rugosus fuscatus.
They seemed to have just begun to emerge from their nests. Most of them were tentatively walking around the nest entrance. They were doing a little bit of excavating and exploring, but no foraging that I could see.
They were very calm. I’m pretty sure that they knew I was there, but they just carried on with their business without the mad charging behavior I’d seen in Pogonomyrmex occidentalis.
There were some beautiful black conglomerate rocks near some of the nests. The ants seemed to enjoy walking on these – I’m assuming that the warmth of the rocks felt good. The ants seemed to almost disappear against the black rocks.
There were a few lichen-encrusted patches in the rocks. I thought that I saw the ants gnaw at the lichen occasionally, though I’m not sure about that.
I am sure that the ants were beautifully photogenic against the lichens. I took a lot of photos of them – probably fifty or sixty shots. The ants’ beautiful dark coloration made exposure tricky. I needed to have enough light so that their dark eyes were visible, but not so much light that I got big white over-exposure blotches from the ants’ shiny, reflective bodies.
As is typical of my ant photography attempts, only a very few of those shots came out. Most were out of focus, out of frame, etc. I am very grateful for the Law of Averages!
After these quite-pleasant interactions, I was curious. Were my interactions with Pogonomyrmex rugosus pleasant (compared with P. occidentalis) because of the difference in elevation and weather on this particular day? Was I just in softer, squishier frame of mind, thus interpreting their behavior in a more benevolent light?
As an experiment, I stopped to photograph a Pogonomyrmex occidentalis nest that was very near some of the Pogonomyrmex rugosus nests. The P. occidentalis mound was built around a large rock, one that would allow me to get low-angle photos without laying on the ground.
The nest entrance was at the top of the nearly vertical slope formed by the rock. There were a few ants out near the nest entrance. I would respectfully take a couple of photos…then things would change. Fifteen, twenty, perhaps more Pogonomyrmex occidentalis workers would come pouring out of the nest entrance, charging towards me.
Have you ever seen the movie World War Z? There’s a scene in which tge zombies pour off of a high cliff or wall, disregarding their personal safety in their zeal to get at the uninfected humans. Even as the zombies were falling, they would be flailing their limbs, trying to make progress towards the humans.
That’s what the Pogonomyrmex occidentalis reminded me of as they charged forward and fell down the steep face of the rock. So I decided that perhaps discretion was the better part of valor, and didn’t get a lot of photos of them on this particular day 🙂
I am, again, astonished at the difference in temperament between species which I’ve always assumed were ecologically similar.
