Over the past 3 decades, Gordon has studied the behavior, demography and ecology of a population of about 300 harvester ant colonies in Arizona, using both field and laboratory experiments. This is the longest-running study monitoring any social insect population with long-lived colonies of known age. A colony is founded by a single queen and lives for 20-30 years. Because the ages of the colonies are known, the long-term study has made it possible to learn how colony behavior changes as the colony grows older and larger. The work has included studies of behavior, ecology, demography and chemical communication. Recent studies used genetic variation to identify the relation between parent and offspring colonies. This in turn made it possible to track how natural selection is shaping the collective regulation of foraging in this species. Visualization of the spatial history of this population will contribute to future demographic and ecological studies, and to genetic work examining the heritability of collective behavior from parent to offspring colonies.