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I mentioned in recent post that the black harvester ants Messor pergandei are also reported in the older literature as Veromessor pergandei.

After seeing a 2017 article which used the name Veromessor, I decided ask for an update from one of the authors, Dr. Christina Kwapich, who is currently at Arizona State University.

Dr. Kwapich was kind enough to explain that the status of the name had been up in the air until Ward et al. (2015) used DNA techniques to sort it out during a major revamping to the ant subfamily Myrmicinae. So, Veromessor pergandei it is.

Check out Dr. Kwapich's research on Veromessor in this video.

Ant research at Arizona State University from ASU Now on Vimeo.

She let us know that she's doing some work on worker size and nest architecture that will come out this summer. We're looking forward to it.

Kwapich, C. L., Gadau, J., & Hölldobler, B. (2017). The ecological and genetic basis of annual worker production in the desert seed harvesting ant, Veromessor pergandei. Behavioral Ecology and Sociobiology, 71(8), [110]. DOI: 10.1007/s00265-017-2333-1

Ward, P.S. S. G. Brady, B. L. Fisher, T. R. Schultz. (2015). The evolution of myrmicine ants: phylogeny and biogeography of a hyperdiverse ant clade (Hymenoptera: Formicidae). Systematic Entomology. 40 (1): 61–81. DOI: 10.1111/syen.12090

It rained last night and it was about 40° F this morning, so I had trouble finding insects to photograph.

I did find something in this decomposing grapefruit:

rover ants.

Nothing ever seems to faze rover ants.

A friend is building a new house and he wanted to know about the ant colonies he found in his yard.

Photograph by Bill Webster

These shiny black ants are Messor pergandei (also seen in the literature as Veromessor.) They are a type of harvester ant, which means they collect, process, and store seeds as their main food source (See previous post).

Nearby was another ant colony.

Photograph by Bill Webster

Although these ants look similar superficially to those above, on closer inspection their bodies are dark maroon-red rather than black, particularly in the mid section. They also have fine parallel grooves on their heads. Theses ants are harvesters known as Pogonomyrmex rugosus.

Although both these species harvest similar types of seeds, it is not uncommon to find them living near each other. Robert Johnson (1992) suggests that they may segregate over broad regions based on soil texture, but coexist together in regions of overlap.

Some of Bill's earlier photographs showed the ants had placed a ring of wood fragments from construction as a barrier around their colony. It would be interesting to see whether they were reacting to conspecific colonies or those of other species.

Wouldn't it be cool to have ant neighbors like these?

For more information:

Kwapich, C.L., Gadau, J. & Hölldobler, B. (2017) The ecological and genetic basis of annual worker production in the desert seed harvesting ant, Veromessor pergandei.
Behav Ecol Sociobiol 71: 110. https://doi.org/10.1007/s00265-017-2333-1 (link)

Johnson, R.A. (1992) Soil texture as an influence on the distribution of the desert seed-harvester ants Pogonomyrmex rugosus and Messor pergandei
Oecologia 89: 118. https://doi.org/10.1007/BF00319023 (link)

Johnson, Robert A. 1991. Learning, Memory, and Foraging Efficiency in Two Species of Desert Seed-Harvester Ants. Ecology 72: 1408- 1419. (link)

Rissing, S.W. (1988) Dietary similarity and foraging range of two seed-harvester ants during resource fluctuations. Oecologia 75: 362. https://doi.org/10.1007/BF00376938 (link)

3

People who go to u-pick vegetable farms usually come home with lettuce or corn or tomatoes. When I went to a u-pick vegetable farm near Phoenix, Arizona, I came home with photographs of ants, instead.

It wasn't surprising to see numerous circular mounds with a single entrance hole in the center.

The nests are made by a common ant in the low desert, Dorymyrmex bicolor. As I've written previously, D. bicolor seems to prefer to nest along dirt paths or roads. The garden had plenty of those.

Here's another nest, again with an entrance hole in the center, and covered with active ants.

The workers here were pulling out clumps of what looked like dirt. Can you see the single petiole that is characteristic of the species?

After seeing about three dozen or so circular nests like those above, I found this one.

Same rough shape, but notice anything different?

Where are all the ants?

From another view, the entrance hole is actually blocked with dirt.

Finally, I can see some ants, but those aren't Dorymyrmex bicolor workers.

The workers exiting from this nest are uniform in color. They have a petiole and a postpetiole.  Notice anything else about them?

The Dorymyrmex worker ants from the same perspective have large eyes. See any noticeable eyes from this view?

Having no noticeable eyes is a characteristic of Neivamyrmex army ants (Note:  They do have a single eye facet, but it isn't obvious.)

The exact species is much more difficult to figure out.

Wayne P. Armstrong found some similar Neivamyrmex near the Superstition Mountains in Arizona, which are close to the farm where I found these ants. Gordon Snelling identified Armstrong's ants as Neivamyrmex leonardi. The ones I found could be N. leonardi or one of several similar species.

In any case, Neivamyrmex army ants resemble their larger namesakes because they are always on the move. They don't make permanent or long term nests like the Dorymyrmex, but instead raid nests of other ants stealing the brood for food. Seems like in this case a Dorymyrmex bicolor colony was a target of their raid. Armstrong reports Neivamyrmex workers raid Pheidole nests, as well.

So, I didn't bring home lettuce, but maybe something even better from the u-pick farm.

Have you ever seen Neivamyrmex army ants?