Data from: Effects of feral cats on the evolution of anti-predator behaviours in island reptiles: insights from an ancient introduction

Exotic predators have been the driving force behind the extinction of many island endemic species. We examined impacts of feral cats (Felis catus) on the abundance and anti-predator behaviors of Aegean wall lizards (Podarcis erhardii) in the Cyclades (Greece), where cats were introduced thousands of years ago. We compared populations with high and low cat density on Naxos and populations on surrounding islets with no cats. Results show that cats have strong negative effects on wall lizard populations, and lizards cope with current threat from cats using plastic defenses that likely existed before the ancient introduction. Lizards facing greater risk from cats stayed closer to refugia, and were more likely to shed their tails in a standardized assay. Flight initiation distance from a surveyor or a mounted cat decoy in the lab correlated closely with risk from cats. All populations showed phenotypic plasticity in flight initiation distance suggesting that this plasticity is ancient and could have helped wall lizards survive the initial introduction of cats to the region. Lizards from islets sought shelter less often and often initially approached the cat decoy. These differences reflect a change since the introduction and could render islet lizards strongly susceptible to cat predation.

外来捕食者是诸多岛屿特有物种灭绝的核心驱动因素。本研究以希腊基克拉泽斯群岛为研究区域，该区域于数千年前引入了野化家猫（Felis catus）种群，旨在探究野化家猫对爱琴海壁蜥蜴（Podarcis erhardii）的种群丰度及反捕食行为的影响。我们对比了纳克索斯岛上家猫密度高低不同的蜥蜴种群，以及周边无家猫的小岛蜥蜴种群。研究结果表明，家猫对壁蜥蜴种群存在显著的负面影响；而蜥蜴借助极有可能在人类引入家猫之前就已存在的可塑性防御策略，应对当前家猫带来的捕食威胁。面临更高家猫捕食风险的蜥蜴，会更贴近庇护场所活动，且在标准化断尾测试中更易发生尾部自割行为。实验室环境下，蜥蜴对调查人员或静态家猫模型的逃逸起始距离（Flight initiation distance）与其面临的家猫捕食风险高度相关。所有蜥蜴种群均在逃逸起始距离上表现出表型可塑性（phenotypic plasticity），这表明该可塑性起源久远，或曾助力壁蜥蜴在人类最初引入家猫的阶段得以存活。来自无家猫小岛的蜥蜴则更少寻求庇护，且通常会主动靠近家猫模型。这些差异反映了家猫引入后种群发生的适应性变化，也可能使得无家猫小岛的蜥蜴极易遭受家猫捕食。