Data from: Infanticide as a male reproductive strategy has a nutritive risk effect in brown bears

Behavioral strategies to reduce predation can incur costs (i.e. risk effects). A common strategy to avoid predation is spatiotemporal avoidance of predators, in which prey typically trade optimal resources for safety. Analogous with predator-prey theory, risk effects should also arise in species with sexually selected infanticide (SSI), in which females with dependent offspring avoid infanticidal males. In brown bears (Ursus arctos), SSI is common and explains spatiotemporal segregation among reproductive classes. Here, we show that females with cubs-of-the-year had lower quality diets than conspecifics during the SSI high-risk period, the mating season. After the mating season, their diets were of similar quality to diets of their conspecifics. Our results suggest a nutritive risk effect of SSI, in which females with cubs-of-the-year alter their resource selection and trade optimal resources for offspring safety. We suggest that risk effects can be widespread among species with SSI, and that these risk effects can add to the female costs of reproduction.降低捕食风险的行为策略往往会产生相应代价（即风险效应）。规避捕食的常见策略为在时空上远离捕食者，此时猎物通常会以最优资源换取生存安全。与捕食者-猎物理论类似，存在性选择杀婴（sexually selected infanticide, SSI）的物种中也应存在此类风险效应：携带依赖其抚育后代的雌性会避开具有杀婴倾向的雄性。在棕熊（Ursus arctos）种群中，性选择杀婴现象普遍存在，且该现象可解释不同繁殖类群间的时空分隔格局。本研究发现，在性选择杀婴的高风险时期——发情交配季，携带当年幼崽的雌性棕熊的日粮质量低于同种其他个体；而交配季结束后，它们的日粮质量则与同种个体无显著差异。研究结果表明，性选择杀婴存在营养风险效应：携带当年幼崽的雌性棕熊会改变其资源选择策略，以最优资源换取后代的生存安全。我们推测，此类风险效应在存在性选择杀婴的物种中可能广泛存在，且这类风险效应会进一步增加雌性个体的繁殖代价。