Kronauer studies social evolution and behavior within complex societies. The sophisticated behavior, communication, and division of labor within ant colonies makes these social insects ideal model systems for this work. His lab uses an integrative approach to understand how natural selection shapes the evolution of insect societies and how social life is regulated at the levels of genes, individuals, and colonies.
Insect societies are socially integrated to such an extent that they are often portrayed as “superorganisms” in which different morphological or behavioral castes have different functions, similar to the tissues of an organism. The Kronauer lab uses ants to study a number of broad questions: How did complex animal societies evolve from solitary ancestors? How does behavioral and developmental plasticity give rise to division of labor? How do individual ants produce, perceive, and process social signals? And how does the composition and network structure of social groups affect group-level properties and fitness?
To address these questions, the lab uses molecular genetics and neuroscience in combination with quantitative behavioral and morphological measurements under controlled laboratory conditions. In particular, the researchers are developing and using the clonal raider ant Ooceraea biroi as a new model system for social behavioral genetics.
The clonal raider ant is a powerful model system because it uniquely combines the rich biology of social insects with unparalleled experimental accessibility. Colonies consist of totipotent, clonally reproducing, genetically identical workers, while queens are absent. This allows researchers to set up many experimental colonies of arbitrary sizes from stock colonies, precisely controlling and replicating the genetic composition of social groups. Different clonal genotypes can be mixed in experimental colonies. Moreover, all individuals in a colony undergo synchronized behavioral and reproductive cycles, alternating between reproductive phases during which workers lay eggs, and brood care phases during which different workers specialize on different tasks, such as nursing and foraging. Because of this reproductive synchrony, larvae develop in discrete cohorts, providing unparalleled experimental control over individual age and group demography.
Taken together, the unusual biology of the clonal raider ant makes it possible to control and replicate the size, genotypic composition, and age structure of colonies—the three central factors affecting individual behavior, division of labor, and social networks in ants. The Kronauer lab has recently published the species’ genome and has developed protocols for genome editing along with automated tracking setups that allow precise quantification of individual behavior and social interaction networks.