Data from: The adaptive value of gluttony: predators mediate the life history trade-offs of satiation threshold

Animals vary greatly in their tendency to consume large meals. Yet, whether or how meal size influences fitness in wild populations is infrequently considered. Using a predator exclusion, marked-recapture experiment, we estimated selection on the amount of food accepted during an ad libitum feeding bout (hereafter termed "satiation threshold") in the wolf spider Schizocosa ocreata. Individually marked, size-matched females of known satiation threshold were assigned to predator exclusion and predator inclusions treatments and tracked for a 40 day period. We also estimated the narrow sense heritability of satiation threshold using dam on female offspring regression. In the absence of predation, high satiation threshold was positively associated with larger and faster egg case production. However, these selective advantages were lost when predators were present. We estimated the heritability of satiation threshold to be 0.56. Taken together, our results suggest that satiation threshold can respond to selection and begets a life history trade-off in this system: high satiation threshold individuals tend to produce larger egg cases but also suffer increased susceptibility to predation.

不同动物的大量进食倾向存在显著差异。然而，针对野生种群而言，进食量是否以及如何影响个体适合度（fitness），这一问题却鲜有探讨。本研究借助捕食者排除结合标记-重捕实验，对饰棍螯狼蛛（Schizocosa ocreata）在自由取食时段内所摄入食物量（下文简称“饱足阈值（satiation threshold）”）所受的自然选择压力进行了估算。我们将经个体标记、体型匹配且已知饱足阈值的雌性个体分配至捕食者排除组与捕食者存在组，开展为期40天的跟踪监测。此外，我们通过母本-雌性子代回归分析，估算了饱足阈值的狭义遗传力（narrow sense heritability）。结果显示，在无捕食者的环境中，较高的饱足阈值与更大卵囊的产生及更快的产卵速率呈正相关；但当存在捕食者时，这类选择优势便不复存在。我们估算得到饱足阈值的狭义遗传力为0.56。综合来看，本研究结果表明，饱足阈值可响应自然选择压力，并在该系统中引发生活史权衡：饱足阈值较高的个体往往能产出更大的卵囊，但同时也会面临更高的捕食易感性。