Interactions with Plants

From seed foraging to plant removal. Pogos interacting with the plant life around them, in North America.
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Pogonomyrmex salinus

● Wanapum Rec. Area [Kittitas Co], WA USA [el. 190 m / 623 ft] view location in Google Maps » ● 5/10/09 12:43PM sunny, air temp: 23°C / 74°F

A Pogonomyrmex salinus forager taking possession of a cheatgrass (Bromus tectorum) spikelet that had likely been cut from the plant by this ant, or by a nestmate - the object was then carried back to the nest as a potential source of nutrition. [scroll down for additional notes/references - also see previous image]

ADDITIONAL NOTES/REFERENCES: The introduced (and invasive) grass Bromus tectorum (cheatgrass), is common in many of the areas inhabited by Pogonomyrmex ants, and is often a target of their foraging activities. One study in central Oregon found cheat grass (Bromus tectorum), to be one of the 5 most frequently collected seeds by P. salinus. The others were: Phacelia linearis, Hordeum jubatum, Descurainia pinnata, and Sisymbrium altissimum. Pogonomyrmex occidentalis (a member of the same complex as P. salinus) has long been known to have an association with Bromus tectorum, though there are indications that this ant prefers other species when they are available. In the Twin Falls, Idaho area, Cole found the seeds of B. tectorum to be harvested in great quantities "...primarily due to the predominance of Bromus tectorum in the semi-desert areas." He also notes that "the seed chambers of mounds in dense bromegrass areas often contain a greater quantity of other seeds and only a few colonies were located which seemed to harvest bromegrass seeds exclusively." This seems to be in keeping with the preliminary findings of a study of P. occidentalis in Colorado, by D. Wiernasz, where it was found that "Bromus tectorum was strongly avoided, and never exceeded 3% of seeds collected by foragers, even in high density areas." ·Cole, A.C. 1932a. The Relation of the Ant, Pogonomyrmex occidentalis CR., to its Habitat. Ohio Journal of Science, 32:133-46, Ohio State University ·Wiernasz, D. 2005. Granivore Activity on the Invasive Grass Bromus tectorum: a Factor in Establishment or Exclusion? University of Huston ·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3

pogo pogonomyrmex pogonomyrmex salinus ants interacting with plants macro harvester ants