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The article discusses a study by L. Fishman and J. H. Willis on pollen limitation and natural selection on floral characters in the yellow monkeyflower. Fishman and Willis applied a factorial design of pollen supplementation and pollinator exclusion to plants in an Oregon population of Mimulus guttatus and found that pollen supplementation increased seed production and pollinator exclusion reduced it. The findings imply that Mimulus guttaus plants with different pollinator abundances will be subject to strongly divergent types of selection. According to the study, in declining pollinator populations, the flowers themselves may begin to evolve to be less attractive and less reliant on pollinators, which might lead to declines.

Polyploidy, or whole-genome duplication often with hybridization, is common in eukaryotes and is thought to drive ecological and evolutionary success, especially in plants. The mechanisms of polyploid success in ecologically relevant contexts, however, remain largely unknown. We conducted an extensive test of functional trait divergence and plasticity in conferring polyploid fitness advantage in heterogeneous environments, by growing clonal replicates of a worldwide genotype collection of six allopolyploid and five diploid wild strawberry (Fragaria) taxa in three climatically different common gardens. Among leaf functional traits, we detected divergence in trait means but not plasticities between polyploids and diploids, suggesting that increased genomic redundancy in polyploids does not necessarily translate into greater trait plasticity in response to environmental change. Across the heterogeneous garden environments, however, polyploids exhibited fitness advantage, which was conferred by both trait means and adaptive trait plasticities, supporting a 'jack-and-master' hypothesis for polyploids. Our findings elucidate essential ecological mechanisms underlying polyploid adaptation to heterogeneous environments, and provide an important insight into the prevalence and persistence of polyploid plants., (No claim to original US government works New Phytologist © 2018 New Phytologist Trust.)

Premise of the Study: Recurrent formation of polyploid taxa is a common observation in many plant groups. Haploid, cytoplasmic genomes like the plastid genome can be used to overcome the problem of homeologous genes and recombination in polyploid taxa. Fragaria (Rosaceae) contains several octo- and decaploid species. We use plastome sequences to infer the plastid ancestry of these taxa with special focus on the decaploid Fragaria cascadensis., Methods: We used genome skimming of 96 polyploid Fragaria samples on a single Illumina HiSeq 3000 lane to obtain whole plastome sequences. These sequences were used for phylogenetic reconstructions and dating analyses. Ploidy of all samples was inferred with flow cytometry, and plastid inheritance was examined in a controlled cross of F. cascadensis., Key Results: The plastid genome phylogeny shows that only the octoploid F. chiloensis is monophyletic, all other polyploid taxa were supported to be para- or polyphyletic. The decaploid Fragaria cascadensis has biparental plastid inheritance and four different plastid donors. Diversification of the F. cascadensis clades occurred in the last 230,000 years. The southern part of its distribution range harbors considerably higher genetic diversity, suggestive of a potential refugium., Conclusions: Fragaria cascadensis had at least four independent origins from parents with different plastomes. In contrast, para- and polyphyletic taxa of the octoploid Fragaria species are best explained by incomplete lineage sorting and/or hybridization. Biogeographic patterns in F. cascadensis are probably a result of range shift during the last glacial maximum., (© 2018 The Authors. American Journal of Botany is published by Wiley Periodicals, Inc. on behalf of the Botanical Society of America.)