Army Ants in Columbia California

I found a nest of army ants while looking for ants, and more specimens of the unknown species of green lacewing, in the Gold Springs subdivision, in Columbia California, in Tuolumne County.

Dr. Philip Ward has identified, based on sample sent to him, that these are army ant workers, of the species Neivamyrmex opacithorax.

This was the first time I had found an actual nest of these ants, since seeing my first specimens decades ago in the Wards Creek Road area. These ants are rare, or at least hard to find. There are some photos showing where the nest was found, at the bottom of this post.

According to Dr. Philip Ward, “there are three species of Neivamyrmex in northern California (N. nigrescensN. californicus, and N. opacithorax). They are active predominantly at night – and hence may be more common than we realize. These three species prey mostly on other ants and occasionally on termites. They are nomadic, that is to say, they do not have permanent nests. After they deplete their food supply in one area they move on. Army ants are now absent from most urban areas in California because they have been eliminated by the introduced Argentine ant (Linepithema humile). They are no match for this aggressive, introduced ant species.

Notice that these ants are almost blind; they have no eyes, except, as the literature says, a single eye facet. They don’t bite and they don’t sting. They are harmless and beneficial.

30 May 2019 Columbia CA

the army ant nest was under the small rock, between the stump and the large boulder on the right side of the image.
This is where the army ant nest was located. It was under the rock next to the old stump.