Data from: Young giant water bug nymphs prefer larger prey: changes in foraging behavior with nymphal growth in Kirkaldyia deyrolli

Raptorial characteristics may evolve in predators because of their importance in obtaining food. The giant water bug, Kirkaldyia deyrolli, possesses a claw on the terminal segment of the raptorial foreleg that is crucial for capturing prey. Claw curvature has been previously shown to change during growth in this species, but the adaptive significance of this change has not yet been explored. Predation experiments have demonstrated that young nymphs with highly curved claws caught proportionally larger prey than older nymphs with less-curved claws. Catching behaviours for a certain prey size differed significantly between young and older nymphs. The observation that nymphal growth affects prey-catching behaviour in the giant water bug supports the hypothesis that predators can change catching behaviours based on changes in raptorial characteristics in order to maximize prey resources acquired at each developmental stage.

掠捕式特征（raptorial characteristics）在捕食者类群中可能发生演化，因其在食物获取过程中具有关键作用。迪氏巨水蝽（Kirkaldyia deyrolli）的掠捕式前足末端体节生有爪结构，该结构对其捕食猎物至关重要。此前已有研究证实，该物种在生长发育期间其爪的曲率会发生改变，但这一变化的适应性意义迄今尚未得到探索。捕食实验结果表明，爪曲率较高的低龄若虫，相较于爪曲率更低的高龄若虫，能够捕捉到体型相对更大的猎物；针对特定体型猎物的捕食行为，在低龄与高龄若虫之间亦存在显著差异。本次观测发现迪氏巨水蝽的若虫生长会影响其捕食行为，这一结果支持了如下假说：捕食者可依据自身掠捕式特征的变化调整捕食行为，从而最大化其在每个发育阶段所能获取的猎物资源。