The role of self-fertilization in plant colony establishment

Abstract

Increased rates of self-fertilization are often found in plant colonies, but the factors driving the observed higher selfing rates remain unclear. Specifically, the higher selfing rates in colonist populations may be due to 1) source populations with a higher selfing rate being more likely to successfully establish colonies (a filter effect), 2) the in situ evolution of selfing rate or a plastic selfing rate increase rescuing the colony from extinction, 3) selfing rate evolution post establishment. Using individual-based simulations and eco-evo models, we show that under both single and multiple dispersal, colony establishment may often be driven by a filter effect, due to a higher initial selfing rate and lower genetic load, which are correlated since selfing can purge deleterious mutations. Moreover, the role of the filter effect is weaker under multiple dispersal than single dispersal. The evolution of a higher selfing rate is unlikely to contribute directly to colony establishment. Although selfing rate evolution occurs during the colonization process, most of the selfing rate evolution may occur post establishment. Plasticity in selfing rates is more effective in facilitating colony establishment than the evolution of selfing.