Now that the blog is all cleaned up, it is time to get out and spend more time looking for and watching ants.
After checking a specimen under the scope, it was evident these were in the genus Dorymyrmex because there was a protruding bump on the propodeum, which gives them the name “cone” or “pyramid” ant.
Here in Arizona, we regularly see another species in the same genus, Dorymyrmex bicolor, which has a brownish-red head and mesosoma.
The dark-colored western cone ants are generally called Dorymyrmex insanus, although the scientific name has been changing “crazily” over a century, plus the genus seriously needs to be revised (Navajo Nature).
The common name isn’t much better. As indicated by the “insane” species name, these ants are commonly called “crazy ants” because they move erratically. The name crazy ant causes confusion, however, because there are now invasive/pest species with similar names, such as Nylanderia fulva (the tawny or Rasberry crazy ant) or Paratrechina longicornis (the longhorn crazy ant). Perhaps we should stick to cone ants?
Dorymyrmex insanus are known to inhabit dry, open areas like the Sonoran desert. They live in small colonies (roughly 2000-3000 workers) in the soil. Like many other kinds of ants, they feed on scavenged insects/dead things and also tend aphids for honeydew.
In his book Adventures Among Ants (reviewed here), Mark Moffett noted that cone ants have been observed grooming harvester ants. Generally ants fight or avoid each other when they encounter ants of a different species, but these cone ants were photographed licking a much-larger Pogonomyrmex worker and leaving it unharmed. James Trager calls cone ants the “cleaner fishes” of the ant world. You can see his photograph at BugGuide.
Have you ever seen Dorymyrmex insanus ants? Where did you find them?
Reference: Snelling, Roy R. 1995. Systematics of the Nearctic genus Dorymyrmex (Hymenoptera: Formicidae). Contributions in Science (Los Angeles) 454:1-14. (Available as free .pdf)