Identifying Pogonomyrmex in Arizona: Part 1

In his book Bees, Wasps, and Ants: The Indispensable Role of Hymenoptera in Gardens, Eric Grissell laments that ant species are difficult to tell apart, more difficult than other types of insects that he has worked with in any case. Most of the time, I would disagree. When it comes to telling apart the harvester ants of the genus Pogonomyrmex, however, I can definitely see his point.

I grew up in the East, so I had never seen Pogonomyrmex before moving to Arizona. That may be part of the problem.

Most pogos look very similar:  reddish brown.

They are all about the same size. Most have spines on the epinotum. They have rugae (ridges) all over the place. Let's just say telling them apart is not black and white.

This year it has been my goal to learn the 14 species of Pogonomyrmex found in Arizona:

  • Pogonomyrmex anergismus
  • Pogonomyrmex apache
  • Pogonomyrmex barbatus
  • Pogonomyrmex bicolor
  • Pogonomyrmex californicus
  • Pogonomyrmex colei
  • Pogonomyrmex  desertorum
  • Pogonomyrmex  huachucanus
  • Pogonomyrmex  imberbiculus
  • Pogonomyrmex  magnacanthus
  • Pogonomyrmex  maricopa
  • Pogonomyrmex occidentalis
  • Pogonomyrmex pima
  • Pogonomyrmex rugosus

Today I'm going to start with one I can identify, Pogonomyrmex californicus.

This is a Pogonomyrmex californicus worker. Can you see the lovely golden hairs under the head that make up the psammophore? This species has a well-developed psammophore.

Our local Phoenix, Arizona-area P. californicus workers have a distinct black gaster, which isn't true of the species elsewhere in its range.

I have noticed that the workers often run with their gaster held up, like this one.

Of the species found in Arizona, only P. bicolor is similar to P. californicus in color, but bicolor workers definitely have spines on the epinotum, whereas californicus workers lack them.

Only 13 more to go 🙂

If you are looking for information about harvester ants, Pogolumina is the go-to place for Pogonomyrmex

One thought on “Identifying Pogonomyrmex in Arizona: Part 1

  1. James C. Trager

    "epinotum" - Now usually called propodeum, to use the same terminology as other hymenopterists.

    Anyway, this species really looks different on the West coast, but is fairly similar in the interior California deserts to the bicolored beauty pictured above. Ant taxonomists disdain the subspecies category, but this case, if indeed the coastal and interior populations are the same species, would be a case where it could apply.

    Enjoy your learning curve. 🙂

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