Abstract Escaping the control of natural enemies is thought to heavily influence the establishment success and impact of non-native species. Here, we examined how the profitability of alternative prey in combination with the presence of a competitor and predator aggressive behavior explain individual differences in diet specialization and the consumption of the invasive green porcelain crab Petrolisthes armatus by the native mud crab predator Panopeus herbstii. Results from bomb calorimetry estimates show that invasive P. armatus has high caloric value relative to alternative native prey. Laboratory assays indicated that specialization and consumption of invasive P. armatus was mostly exhibited by large, female P. herbstii, but the presence of a competitor and predator aggressiveness did not influence diet and the consumption of P. armatus. Thus, intrinsic factors (e.g., sex and body size) seem to explain consumption of P. armatus and dietary specialization in P. herbstii, more generally. Although there are still many predator individuals that do not consume P. armatus, the proportion of individuals that have begun to specialize on P. armatus suggests that for some, it has become more profitable relative to alternative native prey. Given the high caloric value of P. armatus, we suggest that it is likely that differences in the cost of its consumption, including attack, capture, and handling times relative to alternative prey, determine its net profitability to individual predators.

中文翻译：

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性别、大小和猎物热量值影响本地捕食者对入侵猎物的饮食特化和消耗

摘要 摆脱天敌的控制被认为会严重影响非本地物种的建立成功和影响。在这里，我们研究了替代猎物的盈利能力与竞争者和捕食者侵略行为的存在相结合，如何解释饮食专业化的个体差异以及本地泥蟹捕食者 Panopeus policestii 对侵入性绿色瓷蟹 Petrolisthes armatus 的消费。炸弹量热法估计的结果表明，相对于替代的本地猎物，侵入性 P. armatus 具有较高的热量值。实验室分析表明侵入性 P. armatus 的特化和消耗主要由大型雌性 P. herbstii 表现出来，但竞争者和捕食者的攻击性的存在并不影响 P. armatus 的饮食和消耗。因此，内在因素（例如，性别和体型）似乎更普遍地解释了 P. armatus 的消费和 P. herbstii 的饮食专业化。尽管仍有许多捕食者个体不食用 P. armatus，但开始专门研究 P. armatus 的个体比例表明，对于某些人来说，相对于替代的本地猎物，它已经变得更有利可图。鉴于 P. armatus 的高热量值，我们认为它的消费成本（包括相对于替代猎物的攻击、捕获和处理时间）的差异很可能决定了它对个体捕食者的净盈利能力。尽管仍有许多捕食者个体不食用 P. armatus，但开始专门研究 P. armatus 的个体比例表明，对于某些人来说，相对于替代的本地猎物，它已经变得更有利可图。鉴于 P. armatus 的高热量值，我们认为它的消费成本（包括相对于替代猎物的攻击、捕获和处理时间）的差异很可能决定了它对个体捕食者的净盈利能力。尽管仍有许多捕食者个体不食用 P. armatus，但开始专门研究 P. armatus 的个体比例表明，对于某些人来说，相对于替代的本地猎物，它已经变得更有利可图。鉴于 P. armatus 的高热量值，我们认为它的消费成本（包括相对于替代猎物的攻击、捕获和处理时间）的差异很可能决定了它对个体捕食者的净盈利能力。