1,721,021 research outputs found
Specificity in pollination and consequences for postmating reproductive isolation in deceptive Mediterranean orchids
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Just what is a genus? Comparing levels of postzygotic isolation to test alternative taxonomic hypotheses in Orchidaceae subtribe Orchidinae
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Urbanization affects population connectivity, reproductive success and phenotypic traits in the Mediterranean cliff species Brassica incana (Brassicaceae)
No full textBiotic and abiotic changes induced by urbanization can highly affect the ecology and evolution of plant species. Indeed, urban development can have a major impact on plant population genomics, reproductive success and phenotypic traits hence influencing the adaptive strategies and the ecological functions of plant species within ecosystems. Through a holistic study of the impact of urbanization on the genetic and ecological dynamics of a Mediterranean plant species, we shed light on the mechanisms driving plant responses to urban environments. By focusing on 15 populations of the Mediterranean cliff species Brassica incana distributed along an urbanization gradient, we first analyzed the potential drivers of among-population genomic differentiation using a landscape genomics approach. Then, we provided a comprehensive understanding of the complex interplay among ecological factors (climate, herbivore damage, pollinator community), reproductive (relative fruit set and seed-ovule ratio) and phenotypic (glucosinolate content, flower number) traits involved in the response of B. incana populations to urban pressures using complementary Structural Equation Modeling (SEM) and correlative approaches. Our results show that urbanization reduces among-population connectivity by influencing the genomic differentiation among populations. Also, according to SEM analysis, urbanization showed direct and indirect (mediated by mean annual temperature) effects on both pollinator community and herbivory levels, and direct and indirect (mediated by honeybees and long-tongued bees) effects on plant reproductive success. Additionally, urban populations showed higher contents of a glucosinolate compound (glucobrassicin). Taken together, our findings suggest that urbanization can shape genomic differentiation, reproductive success and phenotypic variation. We showed that the impact of urbanization is rather complex and is likely mediated by the interplay between direct and indirect effects of abiotic and biotic conditions on B. incana. Overall, we documented how urban development can shape eco-evolutionary dynamics of a cliff species located in a densely inhabited Mediterranean area
Patterns of reproductive isolation in Mediterranean deceptive orchids
No full textThe evolution of reproductive isolation is of central interest in evolutionary biology. In plants, this is typically achieved by a combination
of pre- and postpollination mechanisms that prevent, or limit, the amount of interspecific gene flow. Here, we investigated
and compared two ecologically defined groups of Mediterranean orchids that differ in pollination biology and pollinator specificity:
sexually deceptive orchids versus food-deceptive orchids.We used experimental crosses to assess the strength of postmating
prezygotic, and postzygotic reproductive isolation, and a phylogenetic framework to determine their relative rates of evolution.We
found quantitative and qualitative differences between the two groups. Food-deceptive orchids have weak premating isolation but
strong postmating isolation, whereas the converse situation characterizes sexually deceptive orchids. Only postzygotic reproductive
isolation among food-deceptive orchids was found to evolve in a clock-like manner. Comparison of evolutionary rates, within a
common interval of genetic distance, showed that the contribution of postmating barriers was more relevant in the food-deceptive
species than in the sexually deceptive species. Asymmetry in prezygotic isolation was found among food-deceptive species. Our
results indicate that postmating barriers are most important for reproductive isolation in food-deceptive orchids, whereas premating
barriers are most important in sexually deceptive orchids. The different rate of evolution of reproductive isolation and the
relative strength of pre- and postmating barriers may have implication for speciation processes in the two orchid groups
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