Am Nat. 2019 Oct;194(4):590-612. doi: 10.1086/704780. Epub 2019 Aug 21.
Dispersal of prey from predator-free patches frequently supplies a trophic subsidy to predators by providing more prey than are produced locally. Prey arriving from predator-free patches might also have evolved weaker defenses against predators and thus enhance trophic subsidies by providing easily captured prey. Using local models assuming a linear or accelerating trade-off between defense and population growth rate, we demonstrate that immigration of undefended prey increased predator abundances and decreased defended prey through eco-evolutionary apparent competition. In individual-based models with spatial structure, explicit genetics, and gene flow along an environmental gradient, prey became maladapted to predators at the predator's range edge, and greater gene flow enhanced this maladaptation. The predator gained a subsidy from these easily captured prey, which enhanced its abundance, facilitated its persistence in marginal habitats, extended its range extent, and enhanced range shifts during environmental changes, such as climate change. Once the predator expanded, prey adapted to it and the advantage disappeared, resulting in an elastic predator range margin driven by eco-evolutionary dynamics. Overall, the results indicate a need to consider gene flow-induced maladaptation and species interactions as mutual forces that frequently determine ecological and evolutionary dynamics and patterns in nature.
猎物从无捕食者斑块中的扩散经常通过提供比本地产生更多的猎物来为捕食者提供营养补贴。从无捕食者斑块中到达的猎物也可能已经进化出对捕食者较弱的防御能力，从而通过提供容易捕获的猎物来增强营养补贴。使用局部模型，假设防御和种群增长率之间存在线性或加速权衡，我们证明了无防御猎物的移民通过生态进化的表型竞争增加了捕食者的丰度并减少了受保护的猎物。在具有空间结构、显式遗传和沿环境梯度基因流动的基于个体的模型中，猎物在捕食者的范围边缘对捕食者变得不适应，并且更大的基因流动增强了这种不适应。这种容易捕获的猎物为捕食者提供了一种补贴，从而增强了其丰度，使其更容易在边缘栖息地中生存，扩大了其范围范围，并在环境变化（如气候变化）期间增强了范围转移。一旦捕食者扩张，猎物就会适应它，优势就会消失，导致由生态进化动态驱动的弹性捕食者范围边缘。总的来说，这些结果表明，需要考虑由基因流引起的不适应和物种相互作用作为经常决定自然中生态和进化动态和模式的相互作用力。
