Natural selection and outbreeding depression suggest adaptive differentiation in the invasive range of a clonal plant

Citation

Pantoja PO, Paine CET & Vallejo-Marín M (2018) Natural selection and outbreeding depression suggest adaptive differentiation in the invasive range of a clonal plant. Proceedings of the Royal Society B: Biological Sciences, 285 (1882), Art. No.: 20181091. https://doi.org/10.1098/rspb.2018.1091

Abstract
Analyses of phenotypic selection and demography in field populations are powerful ways to establishing the potential role of natural selection in shaping evolution during biological invasions. Here we use experimental F2 crosses between native and introduced populations of Mimulus guttatus to estimate the pattern of natural selection in part of its introduced range, and to seek evidence of outbreeding depression of colonists. The F2s combined the genome of an introduced population with the genome of either native or introduced populations. We found that the introduced × introduced cross had the fastest population growth rate owing to increased winter survival, clonality and seed production. Our analysis also revealed that selection through sexual fitness favoured large floral displays, large vegetative and flower size, lateral spread and early flowering. Our results indicate a source-of-origin effect, consistent with outbreeding depression exposed by mating between introduced and native populations. Our findings suggest that well-established non-native populations may pay a high fitness cost during subsequent bouts of admixture with native populations, and reveal that processes such as local adaptation in the invasive range can mediate the fitness consequences of admixture.

Keywords
General Biochemistry, Genetics and Molecular Biology; General Immunology and Microbiology; General Agricultural and Biological Sciences; General Environmental Science; General Medicine

Journal
Proceedings of the Royal Society B: Biological Sciences: Volume 285, Issue 1882