An annual life history is often associated with the ability to self-fertilize. However, it is unknown whether the evolution of selfing commonly precedes the evolution of annuality, or vice versa . Using a 2-year common garden experiment, we asked if the evolution of selfing in the normally perennial Arabidopsis lyrata was accompanied by a shift towards the annual habit. Despite their very recent divergence from obligately outcrossing populations, selfing plants exhibited a 39% decrease in over-winter survival after the first year compared with outcrossing plants. Our data ruled out the most obvious underlying mechanism: differences in reproductive investment in the first year did not explain differences in survival. We conclude that transitions to selfing in perennial A. lyrata may be accompanied by a shift towards annuality, but drivers of the process require further investigation.

The transition to self-compatibility from self-incompatibility is often associated with high rates of self-fertilization, which can restrict gene flow among populations and cause reproductive isolation of self-compatible (SC) lineages. Secondary contact between SC and self-incompatible (SI) lineages might re-establish gene flow if SC lineages remain capable of outcrossing. By contrast, intrinsic features of SC plants that reinforce high rates of self-fertilization could maintain evolutionary divergence between lineages. Arabidopsis lyrata subsp. lyrata is characterized by multiple origins of self-compatibility and high rates of self-fertilization in SC-dominated populations. It is unclear whether these high rates of selfing by SC plants have intrinsic or extrinsic causes. We estimated outcrossing rates and examined patterns of pollinator movement for 38 SC and 40 SI maternal parents sampled from an admixed array of 1509 plants sourced from six SC and six SI populations grown under uniform density. Although plants from SI populations had higher outcrossing rates (mean tm = 0.78 ± 0.05 SE) than plants from SC populations (mean tm = 0.56 ± 0.06 SE), outcrossing rates among SC plants were substantially higher than previous estimates from natural populations. Patterns of pollinator movement appeared to contribute to lower outcrossing rates for SC plants; we estimated that 40% of floral visits were geitonogamous (between flowers of the same plant). The relatively high rates of outcrossing for SC plants under standardized conditions indicate that selfing rates in natural SC populations of A. lyrata are facultative and driven by extrinsic features of A. lyrata, including patterns of pollinator movement.