Sexual selection is considered one of the key processes that contribute to the emergence of new species. While the connection between sexual selection and speciation has been supported by comparative studies, the mechanisms that mediate this connection remain unresolved, especially in plants. Similarly, it is not clear how speciation processes within plant populations translate into large-scale speciation dynamics. Here, we review the mechanisms through which sexual selection, pollination, and mate choice unfold and interact, and how they may ultimately produce reproductive isolation in plants. We also overview reproductive strategies that might influence sexual selection in plants and illustrate how functional traits might connect speciation at the population level (population differentiation, evolution of reproductive barriers; i.e. microevolution) with evolution above the species level (macroevolution). We also identify outstanding questions in the field, and suitable data and tools for their resolution. Altogether, this effort motivates further research focused on plants, which might potentially broaden our general understanding of speciation by sexual selection, a major concept in evolutionary biology.

Department of Botany Faculty of Science Charles University Benatska 2 Prague CZ 128 01 Czech Republic

Institute of Botany The Czech Academy of Sciences Zámek 1 Průhonice 252 43 Czech Republic

Laboratory of Environmental Microbiology Institute of Microbiology of the Czech Academy of Sciences Videnska 1083 Prague 14220 Czech Republic

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