PARENT SESSION
Poster Session 35: Evolutionary Ecology
Thursday, August 11, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Evolution of aggregation behavior in marine plankton.
Verdy, Ariane*,1, Flierl, Glenn1, 1 Massachusetts Institute of Technology, Cambridge, MA
ABSTRACT- A physical-biological model is employed to investigate the evolutionary advantages associated with social behavior in populations of marine plankton. Patches and schools form spontaneously when the swimming motion, directed along the gradient of neighbor density, is large enough to overcome dispersion due to the flow and randomness of the movements. We explore under what environmental conditions is social behavior favorable for the survival of the population, given that patchiness increases the reproductive activity, but at the same time attracts predators and involves more competition for food resources. The model simulates the transmission and slow mutation of a gene controlling the aggregation behavior; natural selection determines which of the grouping or non-grouping type becomes dominant. It is found that grouping organisms can dominate when the diffusivity is high and the reproduction is strongly density-dependent. Turbulent stirring and mixing disrupts the patches, but the plankton field remains more spatially intermittent than a passive scalar field; in cases where stirring is strong and prevents patches from forming, the grouping type does not dominate. The model results suggest that aggregation behavior, by enhancing reproduction, represents an advantage for plankton population when mixing occurs rapidly enough for food to remain available to the clustered organisms.
Key words: aggregation behavior, marine plankton, biological-physical model, evolution