Data from: Does cohistory constrain information use? Evidence for generalized risk assessment in nonnative prey

Though prey use a variety of information sources to assess predation risk, evolutionary cohistory with a predator could constrain information use, and nonnative prey might fail to recognize risk from a novel predator. Nonnative prey might instead use generalized risk assessment, relying on general alarm signals from injured conspecifics rather than cues from predators. I tested the influence of shared predator-prey history on information use, comparing responses among three native and four nonnative prey species to chemical cues from a native predator and cues from injured conspecific prey. Nonnative prey demonstrated information generalism: (1) responding stronger to alarm cues released by injured conspecific prey than to cues from predators and (2) responding similarly to alarm cues as to cues from predators consuming injured conspecific prey. By contrast, for native prey, multiple information sources were required to elicit the greatest defense. The influence of other sources of chemical information was not predicted by cohistory with the predator: only one nonnative snail responded to the predator; digestion was important for only two native species; the identity of injured prey was important for all prey; and predator and prey cues contributed additively to prey response. Information generalism, hypothesized to be costly in coevolved interactions, could facilitate invasions as a driver of or response to introduction to novel habitats.

尽管猎物可借助多种信息源评估捕食风险，但与捕食者的协同演化历史会限制其信息利用策略，而外来猎物通常无法识别新型捕食者带来的风险。对此，外来猎物或许会采用泛化的风险评估策略，依赖受伤同种个体释放的通用警戒信号，而非捕食者相关化学线索（chemical cues）。本研究验证了捕食者-猎物协同演化历史对信息利用的影响，比较了3种本土猎物与4种外来猎物对本土捕食者化学线索以及受伤同种猎物相关线索的响应差异。结果显示，外来猎物表现出信息泛化策略（information generalism）：其一，相较于捕食者相关线索，它们对受伤同种猎物释放的警戒信号的响应更强；其二，它们对警戒信号的响应与捕食者捕食受伤同种猎物后释放的线索的响应无显著差异。与之相对，本土猎物需结合多种信息源才能触发最强的防御行为。其他化学信息源的影响无法通过与捕食者的协同演化历史预测：仅1种外来螺类对捕食者线索产生响应；仅2种本土物种的防御行为受消化过程相关线索的调控；受伤猎物的物种身份对所有猎物的响应均有显著影响；捕食者与猎物线索对猎物响应的贡献呈加性效应。信息泛化策略被认为在协同演化的种间互作中存在适应性成本，但其既可作为入侵新生境的驱动因素，也可作为对新生境引入的响应，从而助力外来物种成功入侵。