title: Adaptive divergence in resistance to herbivores in Datura stramonium.
abstract: Defensive traits exhibited by plants vary widely across populations. Heritable phenotypic differentiation is likely to be produced by genetic drift and spatially restricted gene flow between populations. However, spatially variable selection exerted by herbivores may also give rise to differences among populations. To explore to what extent these factors promote the among-population differentiation of plant resistance of 13 populations of Datura stramonium, we compared the degree of phenotypic differentiation (P ST) of leaf resistance traits (trichome density, atropine and scopolamine concentration) against neutral genetic differentiation (F ST) at microsatellite loci. Results showed that phenotypic differentiation in defensive traits among-population is not consistent with divergence promoted by genetic drift and restricted gene flow alone. Phenotypic differentiation in scopolamine concentration was significantly higher than F ST across the range of trait heritability values. In contrast, genetic differentiation in trichome density was different from F ST only when heritability was very low. On the other hand, differentiation in atropine concentration differed from the neutral expectation when heritability was less than or equal to 0.3. In addition, we did not find a significant correlation between pair-wise neutral genetic distances and distances of phenotypic resistance traits. Our findings reinforce previous evidence that divergent natural selection exerted by herbivores has promoted the among-population phenotypic differentiation of defensive traits in D. stramonium.
authors.affiliation: Department of Evolutionary Ecology, Institute for Ecology UNAM , Mexico Distrito Federal , Mexico.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Castillo
authors.affiliation: Departamento de Biología, Universidad Autónoma Metropolitana-Iztapalapa , Mexico Distrito Federal , Mexico.
authors.forename: Pedro L
authors.initials: PL
authors.lastname: Valverde
authors.affiliation: Department of Evolutionary Ecology, Institute for Ecology UNAM , Mexico Distrito Federal , Mexico.
authors.forename: Laura L
authors.initials: LL
authors.lastname: Cruz
authors.affiliation: Laboratory of Evolutionary Entomology, Institute of Biology, University of Neuchâtel , Neuchâtel , Switzerland.
authors.forename: Johnattan
authors.initials: J
authors.lastname: Hernández-Cumplido
authors.affiliation: Department of Evolutionary Ecology, Institute for Ecology UNAM , Mexico Distrito Federal , Mexico.
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Andraca-Gómez
authors.affiliation: Department of Evolutionary Ecology, Institute for Ecology UNAM , Mexico Distrito Federal , Mexico.
authors.forename: Juan
authors.initials: J
authors.lastname: Fornoni
authors.affiliation: Department of Evolutionary Ecology, Institute for Ecology UNAM , Mexico Distrito Federal , Mexico.
authors.forename: Edson
authors.initials: E
authors.lastname: Sandoval-Castellanos
authors.affiliation: Department of Evolutionary Ecology, Institute for Ecology UNAM , Mexico Distrito Federal , Mexico.
authors.forename: Erika
authors.initials: E
authors.lastname: Olmedo-Vicente
authors.affiliation: Facultad de Estudios Superiores Iztacala, UNAM , Estado de México , Mexico.
authors.forename: César M
authors.initials: CM
authors.lastname: Flores-Ortiz
authors.affiliation: Department of Evolutionary Ecology, Institute for Ecology UNAM , Mexico Distrito Federal , Mexico.
authors.forename: Juan
authors.initials: J
authors.lastname: Núñez-Farfán
keywords: Adaptive divergence; Datura stramonium; Divergent natural selection; Genetic drift and restricted gene flow; Leaf trichomes; PST–FST comparison; Plant defense; Plant resistance; Tropane alkaloids