How rapidly do self‐compatible populations evolve selfing? Mating system estimation within recently evolved self‐compatible populations of Azorean Tolpis succulenta (Asteraceae). Issue 24 (20th November 2020)

• Record Type: Journal Article
• Authors: Kerbs, Benjamin; Crawford, Daniel J.; White, Griffin; Moura, Mónica; Borges Silva, Lurdes; Schaefer, Hanno; Brown, Keely; Mort, Mark E.; Kelly, John K.
• Is Part Of: Ecology and evolution. Volume 10:Issue 24(2020)
• Page Start: 13990
• Page End: 13999
• Publication Date: 2020-11-20
• Subjects: island colonization -- mating systems -- self‐incompatibility -- Tolpis succulenta; Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.6992
• Languages: English
• ISSNs: 2045-7758

Abstract

Abstract: Genome‐wide genotyping and Bayesian inference method (BORICE) were employed to estimate outcrossing rates and paternity in two small plant populations of Tolpis succulenta (Asteraceae) on Graciosa island in the Azores. These two known extant populations of T. succulenta on Graciosa have recently evolved self‐compatibility. Despite the expectation that selfing would occur at an appreciable rate (self‐incompatible populations of the same species show low but nonzero selfing), high outcrossing was found in progeny arrays from maternal plants in both populations. This is inconsistent with an immediate transition to high selfing following the breakdown of a genetic incompatibility system. This finding is surprising given the small population sizes and the recent colonization of an island from self‐incompatible colonists of T. succulenta from another island in the Azores, and a potential paucity of pollinators, all factors selecting for selfing through reproductive assurance. The self‐compatible lineage(s) likely have high inbreeding depression (ID) that effectively halts the evolution of increased selfing, but this remains to be determined. Like their progeny, all maternal plants in both populations are fully outbred, which is consistent with but not proof of high ID. High multiple paternity was found in both populations, which may be due in part to the abundant pollinators observed during the flowering season. Abstract : Genome‐wide genotyping and Bayesian inference method (BORICE) were employed to estimate outcrossing rates and paternity in two small plant populations of Azorean Tolpis that have recently evolved self‐compatibility. Surprisingly, the populations are highly outcrossing, suggesting that neither a paucity of compatible mates or pollinators are selecting for selfing and that strong inbreeding depression may select against selfing.