Data from: Prey nutritional state drives divergent behavioural and physiological responses to predation risk

1.Prey species can respond to the risk of predation with a range of antipredator behaviours and physiological changes. While these responses increase chances of survival, they often involve feeding reductions and greater energy expenditure (e.g. increases in metabolic rate). As a consequence, a prey response is constrained by its own nutritional condition. While a number of studies indeed demonstrate that prey in better nutritional condition have stronger antipredator behaviours, we do not yet understand how condition impacts the physiological component of the prey's response. 2.Previous research revealed that Leptinotarsa decemlineata beetles experiencing predation risk improve their offspring's nutritional condition by promoting intraclutch egg cannibalism. Importantly, egg cannibalism decreased offspring vulnerability by increasing larval behavioural responses to chronic predation risk. In this study we test if egg cannibalism similarly impacts larval physiological responses by comparing how risk of predation in cannibals and non-cannibals affects their behaviour (e.g. feeding reductions), metabolic rate and energy stores. 3.We found that non-cannibals did not exhibit antipredator behaviours but responded physiologically, by increasing metabolic rates. In contrast, cannibals responded behaviourally, suppressing feeding, but without altering metabolism. While cannibals and non-cannibals coupled food intake and energy expenditure differently, both reached similar growth rates and had similar energy stores when facing chronic predation risk. 4.These results indicate that increases in predator avoidance behaviours are not merely mirrored by a stronger physiological response. Instead, changes in metabolism appear to ameliorate, within our experimental conditions, the costs associated with the behavioural response. Prey in poorer nutritional state are not less responsive to predators but appear to rely more heavily on physiological responses, demonstrating that how prey integrates behaviour and physiology depends on their own nutritional state.1. 猎物物种可通过一系列反捕食行为与生理变化应对捕食风险。此类响应虽能提升存活概率，但往往伴随进食量减少与能量消耗增加（例如代谢率升高）。因此，猎物的响应会受自身营养状况制约。尽管多项研究确证营养状况更佳的猎物反捕食行为更强，但目前学界尚未明确营养状况如何影响猎物响应的生理组分。 2. 既往研究显示，遭遇捕食风险的马铃薯甲虫（Leptinotarsa decemlineata）可通过促进同簇卵同类相食，改善后代的营养状况。值得注意的是，卵同类相食通过增强幼虫对长期捕食风险的行为响应，降低了后代对捕食的易感性。本研究通过对比捕食风险对发生卵同类相食与未发生该行为的幼虫的行为（如进食量减少）、代谢率及能量储备的影响，验证卵同类相食是否同样会作用于幼虫的生理响应。 3. 研究结果表明，未进行卵同类相食的个体未表现出反捕食行为，但通过提升代谢率产生了生理响应。与之相反，发生卵同类相食的个体产生了行为响应：抑制进食，但未改变代谢水平。尽管两类个体的食物摄入与能量消耗的耦合模式存在差异，但在长期捕食风险下，二者的生长速率与能量储备均无显著差异。 4. 上述结果提示，避敌行为的增强并非单纯伴随着更强的生理响应。相反，在本实验条件下，代谢变化似乎缓解了行为响应所带来的代价。营养状况较差的猎物对捕食风险的响应并未减弱，反而更依赖生理响应，这表明猎物整合行为与生理响应的方式取决于其自身的营养状态。