● Duval Mine Rd, Sahuarita [Pima Co], AZ USA [el. 882 m / 2893 ft] view location in Google Maps » ● 11/06/10 7:50AM sunny, air temp: 17°C / 62°F This Messor pergandei nest was surrounded by a thick layer of 'chaff' - in this case, the discarded remnants of grasses. Often, large parts of grass stems are harvested, then the bulk of this material is dumped around the outside of the nest after the nutritious seeds have been removed. Here, foraging workers can be seen traversing this material as they head out in search of more food for the colony. - Pogolumina - Pogonomyrmex Harvester Ants of North America