Little to fear: largest lizard predator induces weak defense responses in ungulate prey

Non-consumptive effects can strongly influence apex predator ecological function. These effects arise because prey produce often induce costly phenotypic responses to mitigate predation risk. Yet because predator-prey interactions are complex, prey defences may vary considerably. We investigated if the Komodo dragon (Varanus komodoensis), an reptile apex predator, induced multi-scale anti-predator responses in key prey, the Rusa deer (Cervus timorensis) and the wild pig (Sus scrofa). To this end, we examined the temporal and spatial partitioning of habitats by predator and prey, determined the size of ungulate groups as a function of risk, and assessed changes in individual behavior of prey individuals exposed to predator kairomones at feeding stations. Komodo dragon, deer and pig populations exhibited significant, but subtle differences in three habitat preferences, that otherwise indicated high niche overlap. Komodo dragon predation risk, alongside other commonly considered predictor ...非消耗性效应（Non-consumptive effects）可对顶级捕食者的生态功能产生强烈影响。此类效应的产生源于猎物常会诱导出高昂的表型响应，以降低自身遭遇捕食的风险。然而由于捕食者-猎物间的相互关系极为复杂，猎物的防御策略往往存在显著差异。本研究针对爬行动物顶级捕食者科莫多巨蜥（Varanus komodoensis）是否会在其主要猎物——水鹿（Cervus timorensis）与野猪（Sus scrofa）中诱导出多尺度的反捕食响应展开了探究。为此，我们考察了捕食者与猎物对栖息地的时间与空间分区情况，明确了有蹄类动物群的群体规模随捕食风险的变化规律，并评估了在投喂点接触捕食者异种信息素（kairomones）后，猎物个体的行为改变。研究结果显示，科莫多巨蜥、水鹿与野猪的种群在三类栖息地偏好上虽呈现出显著却细微的差异，但这一情况恰恰反映出三者间存在较高的生态位重叠。科莫多巨蜥的捕食风险，连同其他常见的预测因子……