Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695, USA
Department of Environmental Conservation, University of Massachusetts, Amherst, MA 01003, USA.
Proc Biol Sci. 2018 Aug 15;285(1884):20181239. doi: 10.1098/rspb.2018.1239.
Native species are increasingly living in urban landscapes associated with abiotic and biotic changes that may influence patterns of phenotypic selection. However, measures of selection in urban and non-urban environments, and exploration of the mechanisms associated with such changes, are uncommon. Plant-animal interactions have played a central role in the evolution of flowering plants and are sensitive to changes in the urban landscape, and thus provide opportunities to explore how urban environments modify selection. We evaluated patterns of phenotypic selection on the floral and resistance traits of in urban and non-urban sites. The urban landscape had increased florivory and decreased pollen receipt, but showed only modest differences in patterns of selection. Directional selection for one trait, larger floral display size, was stronger in urban compared to non-urban sites. Neither quadratic nor correlational selection significantly differed between urban and non-urban sites. Pollination was associated with selection for larger floral display size in urban compared to non-urban sites, due to the differences in the translation of pollination into seeds rather than pollinator selectivity. Thus, our data suggest that urban landscapes may not result in sweeping differences in phenotypic selection but rather modest differences for some traits, potentially mediated by species interactions.
本地物种越来越多地生活在与非生物和生物变化相关的城市景观中，这些变化可能会影响表型选择模式。然而，城市和非城市环境中的选择措施以及与这些变化相关的机制的探索并不常见。植物-动物相互作用在有花植物的进化中发挥了核心作用，并且对城市景观的变化很敏感，因此为探索城市环境如何改变选择提供了机会。我们评估了在城市和非城市地点的花部和抗性性状上的表型选择模式。城市景观增加了食花和减少了花粉接收，但选择模式仅略有不同。与非城市地点相比，在城市地点，一个特征，即更大的花部展示大小，表现出更强的定向选择。无论是二次选择还是相关选择，在城市和非城市地点之间都没有显著差异。与非城市地点相比，授粉与城市地点更大的花部展示大小的选择有关，这是由于授粉转化为种子而不是传粉者选择性的差异。因此，我们的数据表明，城市景观可能不会导致表型选择的全面差异，而是某些特征的适度差异，这可能是由物种相互作用介导的。
