Sunday, February 21, 2021

Harvester Ants

In late October I came across an industrious group of Harvester Ants.  These ants of the genus Pheidole exhibit dimorphism, having two different sizes of workers; a smaller size dedicated to food gathering and general nest chores along with a larger version that uses its extremely large head in defense of the colony. They are primarily seed gatherers and were busy moving spent flowers into their nest.  I assume there were some edible seeds included with the flowers.

The ants had located their nest in a shallow mound of bare soil.  The plants in the upper right of the photo are Draba cuneifolia, a rare winter annual.  I’ll be checking this plant population later in the year, so I’ll take some time then to see if I can identify these ants to species.


As usual, I was behind on the amount of work I had hoped to accomplish for the day, so I only took the time to get a couple of still shots and a short video.  The huge headed individuals seemed to be constantly on the move.  My presence may have disturbed their normal behavior, but I didn’t notice them until I was almost on top of the nest, so I don’t know what they were up to a few seconds earlier.


  1. Interesting. They looking incredibly different from the two species of Harvester Ants I know in San Diego County when growing up. There are two, one Red Ants and the other Black Harvester Ants. The Black are much bigger than the reds and more agreesive in that they mow down all vegetation materials in the building of various highways to food sources from the main entrance of their nests. The Red never do that. In both they are all the same size, probably about the size of your big ones there.

    Not sure if it's the same, but try photographing when you are down wind of the Ants. If you are upwind they will aggressively come towards you are the moecules in the air they some how detect and become aggitated. Just an idea, you can test it out.

    Thanks for the pics and video.

    1. Hi, Kevin. In general, most California species are a different genera than those species found here in southern Ohio, so there's bound to be some behavioral differences. I think the red California harvester ant is the same species that came with an ant farm I received as a kid back in the 60's.

      Since ants rely a lot on chemical communication, it makes sense that some species could be sensitive to odors produced by potential predators. I'll see what happens the next time I run into this species.