Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, 32611, USA.
Department of Biology, University of Florida, Gainesville, FL, 32611, USA.
Nat Ecol Evol. 2018 Jan;2(1):108-115. doi: 10.1038/s41559-017-0378-1. Epub 2017 Nov 27.
Invasive exotic species are spreading rapidly throughout the planet. These species can have widespread impacts on biodiversity, yet the ability for native species, particularly long-lived vertebrates, to respond rapidly to invasions remains mostly unknown. Here we provide evidence of rapid morphological change in the endangered snail kite (Rostrhamus sociabilis) across its North American range with the invasion of a novel prey, the island apple snail (Pomacea maculata), a much larger congener of the kite's native prey. In less than one decade since invasion, snail kite bill size and body mass increased substantially. Larger bills should be better suited to extracting meat from the larger snail shells, and we detected strong selection on increased size through juvenile survival. Using pedigree data, we found evidence of both genetic and environmental influences on trait expression and discovered that additive genetic variation in bill size increased with invasion. However, trends in predicted breeding values emphasize that recent morphological changes have been driven primarily by phenotypic plasticity rather than micro-evolutionary change. Our findings suggest that evolutionary change may be imminent and underscore that even long-lived vertebrates can respond quickly to invasive species. Furthermore, these results highlight that phenotypic plasticity may provide a crucial role for predators experiencing rapid environmental change.
入侵的外来物种正在全球范围内迅速蔓延。这些物种会对生物多样性产生广泛的影响，但本地物种（尤其是长寿的脊椎动物）迅速应对入侵的能力在很大程度上仍不为人知。在这里，我们提供了证据表明，在北美范围内，随着一种新型猎物——岛屿苹果蜗牛（Pomacea maculata）的入侵，濒临灭绝的信天翁（Rostrhamus sociabilis）的形态发生了迅速变化，这种新型猎物是信天翁原生猎物的一个体型更大的近亲。自入侵以来不到十年的时间里，信天翁的喙部大小和体重显著增加。更大的喙应该更适合从更大的蜗牛壳中提取肉，我们通过幼体存活率检测到了对体型增大的强烈选择。利用系谱数据，我们发现了表型表达既受到遗传因素又受到环境因素的影响的证据，并发现喙部大小的加性遗传变异随着入侵而增加。然而，预测育种值的趋势强调，最近的形态变化主要是由表型可塑性驱动的，而不是微进化变化。我们的研究结果表明，进化可能迫在眉睫，并且强调了即使是长寿的脊椎动物也能迅速应对入侵物种。此外，这些结果表明，表型可塑性可能为经历快速环境变化的捕食者提供了关键作用。
