Data from: Colonization across gradients of risk and reward: nutrients and predators generate species-specific responses among aquatic insects

1. Predation risk and resource abundance are two primary characteristics that determine species abundances and community composition. Colonizing organisms should attempt to minimize the risk of mortality and maximize growth through selection of patches with the highest expected fitness. However, maximizing fitness across multiple gradients of patch quality involves accurate cue assessment, integration, and behavioral responses that consider multiple factors that affect fitness simultaneously. 2. Our goal was to simultaneously and factorially assess the effects of predation risk and resource abundance among an assemblage of aquatic insects to determine the relative importance of each factor, and whether the two factors interact to affect colonization, oviposition, and community assembly. 3. We conducted a field mesocosm experiment in which we crossed predator density (0, 1, 2 fish, Fundulus chrysotus) with supplemental nutrient abundance (0, 4, 8 g rabbit chow) in a 3 × 3 factorial design. We then assayed colonization by natural populations of aquatic beetles and oviposition by Culex mosquitoes. 4. We observed species-specific responses, with many species avoiding fish and some selecting habitats with more nutrients. Nutrients and predator presence only interactively affected oviposition by Culex mosquitoes, and the effect of fish presence exceeded that of nutrients in all but one analysis. 5. Our results illustrate the primacy of predation risk in generating colonization patterns and structuring communities in aquatic habitats, but that colonization responses to variation in multiple components of patch quality are often species-specific. Simultaneous assessments of multiple aspects of patch quality allow for the determination of potential interactions among cue sources and the relative importance of various patch characteristics to colonizers.1. 捕食风险与资源丰度是决定物种种群丰度与群落组成的两大核心特征。定殖生物会通过选择具备最高预期适合度的生境斑块，尽可能降低死亡风险并最大化自身生长速率。然而，要在生境质量的多重梯度上实现适合度最大化，需要精准评估、整合相关信号，并做出兼顾多种影响适合度因素的行为响应。 2. 本研究旨在通过析因设计，同时评估捕食风险与资源丰度对水生昆虫类群的影响，以明确二者各自的相对重要性，以及两者是否会通过交互作用影响定殖、产卵行为与群落构建过程。 3. 我们采用3×3析因设计开展野外中型实验生态系统（mesocosm）研究，设置捕食者密度（0、1、2尾条纹底鳉（Fundulus chrysotus））与补充养分丰度（0、4、8 g兔饲料）的交叉处理组合。随后统计自然迁入的水生甲虫种群定殖情况，以及库蚊（Culex）的产卵行为。 4. 研究结果显示存在物种特异性响应：多数类群会躲避存在鱼类的生境，部分类群则偏好养分含量更高的生境。养分丰度与捕食者存在仅对库蚊的产卵行为产生交互影响，且除一项分析外，鱼类存在的效应均强于养分丰度的效应。 5. 本研究结果表明，捕食风险在塑造水生生境的定殖格局与群落结构中占据首要地位，但针对生境质量多维度变化的定殖响应往往具有物种特异性。同时评估生境质量的多个维度，有助于明确不同信号源之间的潜在交互作用，以及各类生境特征对定殖生物的相对重要性。