Meeting Abstract

11-6  Thursday, Jan. 5 09:15 - 09:30  Frequency Dependent Selection for Rare Genotypes Promotes Genetic Diversity of a Tropical Palm BROWNE, L*; KARUBIAN, J; BROWNE, Luke; Tulane University; Tulane University

Negative frequency dependent selection among species is a key driver of community diversity in natural systems, but the degree to which negative frequency dependent selection shapes patterns of survival and genetic diversity within species is poorly understood. In a five-year field experiment in the Choco rainforests of northwest Ecuador, we show that seedlings of the tropical palm Oenocarpus bataua with rare genotypes had a pronounced survival advantage over seedlings with common genotypes, with effect sizes (i.e., regression coefficients) comparable to that of light availability. This 'rare genotype advantage' led to an increase of population-wide genetic diversity among seedlings compared to null expectations, as predicted by negative frequency dependent selection, and increased reproductive success in adult trees with rare genotypes. We also investigate the role of long-distance seed dispersal in introducing rare genotypes into the population. These results suggest that within-species negative frequency dependent selection of genotypes can shape genetic variation on ecologically relevant timescales in natural systems and may be a key, overlooked source of non-random mortality for tropical plants.