Longevity of Harvester Ant Colonies in Southern Idaho

Abstract

Harvester ant colonies (Pogonomyrmex owyheei Cole) in southern Idaho were monitored periodically for 9 years. Mortality rates indicate that established colonies live 14-30 years (mean = 17). Mounds were commonly reactivated after the death of an old colony; consequently, some may be utilized for many decades. Clearings with active mounds showed almost no change after 9 years of observations while those without active mounds were rapidly filled by annual herbs and then gradually by perennial shrubs. Harvester ants are clearly a very persistent component of cold desert shrub communities.