Data from: Sexual and nonsexual cannibalism have different effects on offspring performance in redback spiders

Sexual cannibalism is often set apart from other forms of cannibalism; however, no studies have directly compared the fitness consequences of these 2 types of cannibalism. Here, we compared the consequences of cannibalism of a male by a female outside the context of mating (referred to as nonsexual cannibalism) and within the context of mating (referred to as sexual cannibalism) for the propensity to remate, fecundity, and offspring traits of female redback spiders Latrodectus hasselti. Although the timing of cannibalism relative to copulation is critical for male fitness, it is still unclear whether it can also influence female fitness, beyond the fertilization of eggs. Our results showed that sexual cannibalism and nonsexual cannibalism had different effects on offspring survival and growth. Sexually cannibalistic females produced offspring that survived better and grew faster than nonsexually cannibalistic or noncannibalistic females. By experimentally manipulating the quality of prey given to offspring, we showed that these effects were dependent on the spiderlings’ diet quality. In particular, the effects of sexual cannibalism on offspring growth and survival were clearer when offspring were, respectively, fed a high-nutrient diet and a low-nutrient diet. However, sexual cannibalism did not increase offspring tolerance to starvation. Additionally, we did not find any effect of nonsexual cannibalism nor sexual cannibalism on female fecundity or subsequent sexual receptivity. As copulation duration did not account for these effects on offspring performance, our findings suggest that copulation occurring simultaneously with cannibalism plays an essential role in the fitness consequences of this behavior.

性食同类（sexual cannibalism）常被单独区分于其他类型的同类相食行为，但目前尚无研究直接比较这两类同类相食的适合度后果。本研究以红背蜘蛛（Latrodectus hasselti）雌性为研究对象，对比了交配情境外（即非性食同类（nonsexual cannibalism））与交配情境中（即性食同类）雌性捕食雄性后，其再次交配倾向、繁殖力及后代性状的差异。尽管交配与同类相食的时序对雄性适合度至关重要，但目前仍不清楚其是否会在卵子受精之外，对雌性适合度产生额外影响。研究结果表明，性食同类与非性食同类对后代存活与生长的影响存在显著差异：经历性食同类的雌性所产后代的存活能力更强、生长速度快于经历非性食同类或未发生同类相食的雌性个体。通过实验操控幼蛛的猎物日粮质量，我们证实上述效应依赖于幼蛛的日粮品质。具体而言，性食同类对后代生长与存活的影响，分别在幼蛛饲喂高营养日粮与低营养日粮时更为显著。不过，性食同类并未提升后代的饥饿耐受性。此外，本研究未发现非性食同类或性食同类对雌性繁殖力或后续性接受度存在任何影响。由于交配时长无法解释上述对后代表现的影响，本研究结果提示，与同类相食同步发生的交配行为，在该行为的适合度后果中扮演着关键角色。