Interactions with Plants

From seed foraging to plant removal. Pogos interacting with the plant life around them, in North America.
Scroll down PAST BOTTOM OF PAGE for complete image description, and CLICK large image to make it even LARGER...
***There may be multiple image pages; use page/image controls below to see them all!***

34 / 36

Pogonomyrmex salinus

● Wananpum Rec. Area [Kittitas Co], WA USA [el. 190 m/623 ft] view location in Google Maps » ● 6/4/09 10:25AM sunny, air temp: 29°C / 85°F

Running frantically over the hot sand, a P. salinus worker carries an Indian rice grass (Achnatherum hymenoides) seed back to her nest. The seeds of this plant apparently serve as a significant source of nutrition for the Pogos at this location. At the time this image was captured, the soil surface temperature had already reached 50.5°C / 123°F, and only a few ants were still active - most had retreated to the relatively cool nest interior. [scroll down for additional notes/references]

ADDITIONAL NOTES/REFERENCES: We usually see all Pogonomyrmex salinus activity cease when the soil surface temperature reaches approx. 55°C / 131°F. It is not unusual for the ground temperature to reach these levels in July and August, as solar radiation heats the sand/soil/gravel - even though the air temperature may only be in the mid 80s°F. When the weather is very warm, it is typical for Pogos to be inactive, and to remain within the nest from late morning, until late afternoon. In a 1965 study, workers of this species, taken from their nest and placed on sand with a surface temp. of 58°C / 136°F, were observed to perish within 30 seconds. ·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