Mathematical Biology Seminar Steve Frank Department of Ecology and Evolutionary Biology University of California Irvine, CA Wednesday, Oct. 21, 2009 3:05pm in LCB 225 Microbial pathogenesis and metabolism: economic and social perspectives Abstract: 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. Collective action arises only through processes that favor coordinated behavior, as in all aspects of biological sociality. 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. Current studies 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 times scales of success. Demographic and timescale factors may explain a significant amount of variation in microbial pathogenesis and metabolism. These processes of demography and timescale play key roles in any aspect of sociality that can be framed in terms of natural selection or economic efficiency.