Data from: Behavioral hypervolumes of predator groups and predator-predator interactions shape prey survival rates and selection on prey behavior

Predator-prey interactions often vary on the basis of the traits of the individual predators and prey involved. Here we examine whether the multidimensional behavioral diversity of predator groups shapes prey mortality rates and selection on prey behavior. We ran individual sea stars (Pisaster ochraceus) through three behavioral assays to characterize individuals’ behavioral phenotype along three axes. We then created groups that varied in the volume of behavioral space that they occupied. We further manipulated the ability of predators to interact with one another physically via the addition of barriers. Prey snails (Chlorostome funebralis) were also run through an assay to evaluate their predator avoidance behavior before their use in mesocosm experiments. We then subjected pools of prey to predator groups and recorded the number of prey consumed and their behavioral phenotypes. We found that predator-predator interactions changed survival selection on prey traits: when predators were prevented from interacting, more fearful snails had higher survival rates, whereas prey fearfulness had no effect on survival when predators were free to interact. We also found that groups of predators that occupied a larger volume in behavioral trait space consumed 35% more prey snails than homogeneous predator groups. Finally, we found that behavioral hypervolumes were better predictors of prey survival rates than single behavioral traits or other multivariate statistics (i.e., principal component analysis). Taken together, predator-predator interactions and multidimensional behavioral diversity determine prey survival rates and selection on prey traits in this system.捕食者-猎物相互作用（Predator-prey interactions）通常会因所涉及的单个捕食者和猎物的性状而产生差异。本研究旨在探究捕食者群体的多维度行为多样性是否会塑造猎物死亡率以及对猎物行为的选择压力。我们对单个赭色海星（Pisaster ochraceus）开展了三项行为测定（behavioral assays），以从三个维度表征个体的行为表型（behavioral phenotype）。随后构建了行为空间（behavioral space）占据量存在差异的捕食者群体，并通过增设阻隔装置，操控了捕食者间的物理互动能力。猎物为暗绿唇螺（Chlorostome funebralis），我们在其被用于中宇宙实验（mesocosm experiments）前，先通过行为测定评估了它们的反捕食行为。随后将猎物集群暴露于捕食者群体中，并记录被捕食的猎物数量及其行为表型。我们发现，捕食者间的相互作用改变了对猎物性状的生存选择（survival selection）：当捕食者无法进行互动时，更为谨慎的螺类存活率更高；而当捕食者可自由互动时，猎物的谨慎性对存活率无影响。我们还发现，行为空间占据量更大的捕食者群体，其捕食的猎物螺数量较同质性捕食者群体高出35%。此外，相较于单一行为性状或其他多变量统计方法（即主成分分析（Principal Component Analysis）），行为超体积（behavioral hypervolumes）能更好地预测猎物存活率。综上，在本实验系统中，捕食者间的相互作用与多维度行为多样性共同决定了猎物存活率以及对猎物性状的选择压力。