Heads of Laboratories
Social insects, like ants, bees, wasps and termites, live in highly complex societies with sophisticated social behavior, communication and division of labor. Members of Dr. Kronauer’s laboratory use an integrative approach to understand how natural selection shapes the evolution of insect societies and how social life is regulated at different hierarchical levels: the gene, the individual and the colony.
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 different tissues of an organism. The networks of mutually attuned specialists have enabled social insects to evolve to ecological dominance in many terrestrial ecosystems. Most fundamentally, some individuals, the workers, often completely forego egg laying and dedicate their lives to colony maintenance, while others, the queens, monopolize reproduction.
Dr. Kronauer uses ants as model systems to study different aspects of social behavior and evolution. His current research focuses on army ants, a large group of nomadic predatory ants that are of particular ecological importance in tropical rainforests around the world. He studies a variety of species in the field as well as under controlled conditions in the laboratory.
One of the goals of Dr. Kronauer’s research group is to understand the evolution of social insect mating systems and how the genetic composition of insect societies affects colony performance and shapes the evolution of individual behavior. Dr. Kronauer has found that army ant queens mate with more males than the queens of any other type of ant, which results in genetically highly diverse colonies. High genetic diversity might be adaptive in the largest and most complex insect societies because it increases colony-level resistance against pathogen infections, improves colony homeostasis and facilitates effective and complex division of labor within the worker force. In at least one army ant species, genetic diversity is achieved by colonies with multiple reproductive queens, rather than by single queens that mate with many males. Ongoing research in the lab also focuses on species that reproduce asexually, which is rare among ants and can result in colonies with genetically identical individuals. Several projects aim at unraveling the genetic mechanisms and social consequences of such idiosyncratic reproductive systems in ants.
Another line of investigation in the Kronauer lab addresses the molecular basis of social behavior and division of labor. In social insects, developmental trajectories, adult physiology and individual behavior are highly dynamic and contingent upon the social environment. A major challenge is to understand how the social environment is perceived by an individual, how the social environment interacts with an individual’s genome to govern gene expression, how this affects individual physiology and behavior and how the altered individual state in turn feeds back into the social environment of the colony. To address these questions, researchers in the Kronauer lab use molecular genetic techniques, experimental manipulations and quantitative behavioral assays under controlled laboratory conditions.
Finally, Dr. Kronauer’s lab also studies the manifold interactions between ants and other organisms. For example, the large societies of army ants constitute a rich resource for a variety of arthropods. A single army ant species, Eciton burchellii, is known to harbor over 300 species of arthropods, including mites, bristletails, wingless flies and beetles. These species are entirely restricted to their host colonies, and beyond scattered taxonomic descriptions, essentially nothing is known about this microcosm. Dr. Kronauer and his collaborators employ DNA barcoding and imaging techniques to inventory army ant symbionts. They also use population genetics and chemical analyses to study symbiont life history, adaptation and coevolution with the ants.
Dr. Kronauer received his diploma in biology from the University of Würzburg in Germany in 2003, where he studied with Bert Hölldobler. He received his Ph.D. in 2007 from the University of Copenhagen in Denmark, where he worked with Koos Boomsma. After a brief postdoctoral assignment at the University of Lausanne, he was elected as a junior fellow to the Harvard Society of Fellows in 2008. Dr. Kronauer joined The Rockefeller University as assistant professor in 2011. He was named a 2012 Searle Scholar.
• Kronauer, D.J.C. et al. Strict monandry in the ponerine army ant genus Simopelta suggests that colony size and complexity drive mating system evolution in social insects. Mol. Ecol. 20, 420–428 (2011).
• Kronauer, D.J.C. et al. Colony fusion and worker reproduction after queen loss in army ants. Proc. Biol. Sci. 277, 755–763 (2010).
• Ugelvig, L.V. et al. Rapid anti-pathogen response in ant societies relies on high genetic diversity. Proc. Biol. Sci. 277, 2821–2828 (2010).
• Kronauer, D.J.C. and Boomsma, J.J. Multiple queens means fewer mates. Curr. Biol. 17, R753–R755 (2007).
• Kronauer, D.J.C. et al. A molecular phylogeny of Dorylus army ants provides evidence for multiple evolutionary transitions in foraging niche. BMC Evol. Biol. 7, 56 (2007).
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