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A few ant nests dot the sides of a walking pathway at a nearby park, so of course I have to check them out.

For the most part the nests are small colonies of southern fire ants, Solenopsis xyloni.

There are also seemingly endless streams of Forelius mccooki workers traveling along the concrete edgers and sidewalks.

While taking photographs of the fire ant middens, I noticed the fire ants had a few visitors standing by an entrance hole.

Millimeters away from the fire ant workers stood two Forelius workers.

 

Curious, I watched for some minutes. The fire ants did not approach the Forelius, and the Forelius remained relatively still. They didn't appear to be investigating the middens.

The Forelius had a nest entrance not too far away. Perhaps they were just nosy neighbors? (I did notice there weren't any Solenopsis visiting them.)

Wayne Armstrong suggests perhaps the relationship isn't entirely benign. In this video, Solenopsis xyloni workers flag their gasters in response to Forelius pruinosus workers encountered at an artificial feeding site. (You will notice the coloration difference between our local S. xyloni compared to his California ones.)

Interestingly, the soldiers don't seem to respond. According to his notes (scroll down to Southern fire ant), the Forelius were ultimately successful in overtaking the food.

Ants of the Southwest has a photograph of a Forelius worker spraying a S. xyloni worker. He reports S. xyloni exoskeletons piled in Forelius middens, which is also reported here.

Even though southern fire ants are chemically well defended, perhaps they are no match for Forelius.

Have you ever encountered these two species?

References:

Obin, Martin & Vander Meer, Robert. (1985). Gaster flagging by fire ants (Solenopsis spp.): Functional significance of venom dispersal behavior. Journal of chemical ecology. 11. 1757-68. 10.1007/BF01012125.

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.

In addition to the Ants of the Southwest Class, the Ant Course is another great way to learn about ants.  It is being offered August 22 to September 1, 2018 in French Guiana at the Nouragues Field station. Seventeen lucky individuals will be chosen to attend.

Sponsored by California Academy of Sciences and Center for the study of biodiversity in Amazonia (CEBA), the Ant Course is intended to help both professionals and interested amateurs learn about identification, behavior, and ecology of ants.

It isn't offered every year. The last time was in 2015. You can see previous faculty and students by visiting the Ant Course yearbook.

If you'd like to apply, there's a link to a Google form towards the top of the page. You will need to complete the application by April 1, 2018, and be prepared to give the name of a reference when you fill it out.

Hop on over to the Ant Course website for full details.

If you have gone in the past, we'd love to hear from you how it was.