Steve Frank: UC Irvine & Santa Fe Institute Department of Ecology and Evolutionary Biology

Current studies of biological sociality tend to ignore two key factors: the consequences of social traits on long-term aspects of survival and fecundity (demography), and the tension between short and long time scales of success. I use several examples from the biology of microbes to illustrate these fundamental processes of sociality, which apply to any problem that can be framed in terms of natural selection or economic efficiency. For those interested in the particular biological examples, here is a brief summary. Microbes secrete molecules to modify their environment. Secretions dislodge and bind iron, manipulate host defenses, build protective biofilm structures, and communicate information to neighboring microbes. Successful modulation of the environment and successful communication require collective action by a large population of microbes. Recent studies show that kin or group selection powerfully shapes the ways in which microbes collectively communicate and modify their environment. Others studies have shown that the basic design of metabolism and cellular biochemistry may also be influenced by social processes. Competition favors fast extraction and use of resources, reducing metabolic efficiency and leading to low yield per unit of resource. I place these microbial processes into the broad framework of economic and life history theories of biology. I also show that demographic and timescale processes lead to new predictions about microbial pathogenesis and metabolism.