Social insects are exemplars of biological complexity and are among the most evolutionarily successful and ecologically dominant animals on earth. We study the behavioral mechanisms and neural basis of social organization and the ecology and genetics of colonies and populations of social insects, with an emphasis on caste, division of labor and brain evolution. Darwin’s sense of wonder was excited by the ant brain’s capability of “extraordinary mental activity with an extremely small absolute mass of nervous matter.” We feel the same way. By exploring the neuroanatomy and neurochemistry of social behavior using immunohistochemistry, confocal microscopy, high-performance liquid chromatography and pharmacological interventions to examine the regulation of task performance and behavioral development, we seek to understand the neural basis of social structure in light of ecology and evolution. Our integrative studies connect sociobiology, neurobiology and ecology to understand the selective forces associated with social brain evolution in ants, and how the brain meets the demands of processing complex information at the level of the individual and society as a whole. Current research centers on the hyperdiverse ant genus Pheidole, leaf-cutter ants and Australian weaver ants. We are also interested in social mechanisms of disease resistance and tropical ant diversity, behavior and ecology.