Ant mazes and astronomy: Harlow Shapley's entomological experiments at Mount Wilson observatory and Pasadena, California

This article explores the entomological research of American astronomer Harlow Shapley (1885–1972). The focus is 1914–1921, the time that Shapley worked as a staff astronomer at Mount Wilson Observatory in the San Gabriel Mountains of California. The years 1919–1920 receive particular attention because they were the most active period for Shapley's ant experiments. During these years, Shapley undertook two primary programmes of study in ant physiology, each centred on a specific species native to Southern California—the velvety tree ant and the California harvester ant. Shapley's ant research was dependent upon the scientific environment of Mount Wilson Observatory because of several benefits and opportunities that the location offered him. The section ‘Observatory ants’ discusses the details of Shapley's research programme as well as the advantages given him by his location. The subsequent section, ‘Indoor ants’, discusses a change in environment for Shapley's ant experiments and how that change, from an outdoor to an indoor setting, changed the scope and nature of his research. This section also discusses the influences that Shapley's work came to have in the disciplines of entomology, ecology, general physiology, and behavioural science. The final section, ‘Living and non-living?’, discusses the impacts that Shapley's ant research came to have on his own later work concerning cosmic evolution and interdisciplinary co-operation among the sciences. In conclusion, we are left with evidence suggesting that Shapley's work in entomology was highly location-dependent while also possessing far-reaching consequences.