title: Estimating selection through male fitness: three complementary methods illuminate the nature and causes of selection on flowering time.
abstract: Our understanding of selection through male fitness is limited by the resource demands and indirect nature of the best available genetic techniques. Applying complementary, independent approaches to this problem can help clarify evolution through male function. We applied three methods to estimate selection on flowering time through male fitness in experimental populations of the annual plant Brassica rapa: (i) an analysis of mating opportunity based on flower production schedules, (ii) genetic paternity analysis, and (iii) a novel approach based on principles of experimental evolution. Selection differentials estimated by the first method disagreed with those estimated by the other two, indicating that mating opportunity was not the principal driver of selection on flowering time. The genetic and experimental evolution methods exhibited striking agreement overall, but a slight discrepancy between the two suggested that negative environmental covariance between age at flowering and male fitness may have contributed to phenotypic selection. Together, the three methods enriched our understanding of selection on flowering time, from mating opportunity to phenotypic selection to evolutionary response. The novel experimental evolution method may provide a means of examining selection through male fitness when genetic paternity analysis is not possible.
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2 Department of Biology, University of Ottawa, Ottawa, Ontario, Canada K1N 6N5 austen.emily@gmail.com.
authors.forename: Emily J
authors.initials: EJ
authors.lastname: Austen
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2 arthur.weis@utoronto.ca.
authors.forename: Arthur E
authors.initials: AE
authors.lastname: Weis
mesh_terms: D029741:Brassica rapa / Q000235:genetics* / Q000254:growth & development; D035264:Flowers / Q000235:genetics / Q000254:growth & development*; D056084:Genetic Fitness; D005821:Genetic Techniques; D008962:Models, Theoretical; D012098:Reproduction; D012641:Selection, Genetic
keywords: experimental evolution; flowering time; genotype–environment covariance; natural selection; paternity analysis; phenology