Cannibalism is a widespread phenomenon in nature, often occurring when food is scarce, for example among predators that have overexploited a local prey population. Instead of cannibalising, predators can disperse, thereby avoiding being cannibalised or cannibalising related conspecifics, which results in inclusive fitness loss. Theory on prey exploitation in ephemeral predator-prey systems predicts that predators may be selected to display prudent predation by dispersing early, thus saving food for their remaining offspring. This is especially advantageous when average relatedness in the local population is high. Less prudent predators refrain from dispersing until all prey are exterminated. These prey exploitation strategies may also have repercussions for cannibalism, especially when it is driven by food shortage. We therefore investigated to what extent adult females and males cannibalise or disperse after prey have been exterminated locally. We used two lines of the haplodiploid predatory mite Phytoseiulus persimilis that were selected for early and late dispersal, respectively. In wind tunnels, we observed the cannibalistic and dispersal behaviour of individual adult predators of these lines on a rose leaf with only conspecific larvae as food. Both selection lines behaved similarly, indicating that selection on dispersal behaviour did not result in correlated effects on cannibalism behaviour. Male predators stayed significantly longer on the leaf and engaged more often in cannibalism than females. The results suggest that there might be gender-specific differences in cannibalistic tendency in relation to dispersal. Future theoretical studies on the evolution of cannibalism and dispersal should take differences between the genders into account.

自相残杀是自然界中普遍存在的现象，通常在食物匮乏时发生，例如在过度捕食当地猎物的掠食者中。捕食者可以驱散食肉，而不是进行食人族化，从而避免被食人族化或食人性相关的同种异体，从而导致包容性丧失。短暂掠食者－猎物系统中的掠食者掠夺理论预测，掠食者可以通过早期散布来表现出审慎的掠食，从而为剩余的后代保留食物。当本地人口的平均相关性很高时，这尤其有利。不那么谨慎的掠食者在所有猎物被消灭之前都不要散布。这些猎物开发策略也可能对同类相食产生影响，尤其是在食物短缺的情况下。因此，我们调查了猎物在当地被灭绝后成年雌性和雄性食人或散食的程度。我们用了两行四倍体捕食性螨分别被选择用于早期和晚期扩散的柿树（Phytoseiulus persimilis）。在风洞中，我们观察到这些株系的成年捕食者在食有同种幼虫的月季叶上的食人行为和传播行为。两条选择线的行为相似，表明对分散行为的选择不会导致对自相残杀行为的相关影响。雄性掠食者在叶子上的停留时间明显更长，并且比雌性更常从事自相残杀。结果表明，与分散相关的食人倾向可能存在性别差异。未来有关食人症和传播的理论研究应考虑性别差异。