Sex differences in the behavioural traits across ontogenetic stages in a sexually-size dimorphic spider

Selection acts differently on females and males due to differences in potential reproductive rates, driving the evolution of sex differences in traits, including growth and behaviour. Additionally, selection pressures vary during an individual's ontogeny, with growth being crucial in early developmental stages and reproduction during adulthood, leading to age- and sex-specific behavioural strategies. In this study, we investigated a sexually-size dimorphic spider, the raft spider (Dolomedes fimbriatus), where females are substantially larger than males. We repeatedly observed spiders from juvenile to adult stages, examining boldness, voracity towards prey, and probability to attack. Our findings revealed that females exhibited greater boldness, voracity, and probability to back-attack the simulated attacker compared to males. Notably, the observed behaviours changed during ontogeny, with sex differences in the magnitudes and directions of change, indicating distinct life history strateg...

由于雌雄个体的潜在繁殖速率存在差异，自然选择对二者的作用模式存在显著分化，进而推动了包括生长与行为在内的多种性状的性别差异演化。此外，选择压力在个体的个体发育（ontogeny）过程中会发生动态变化：早期发育阶段以生长为核心任务，成年个体则以繁殖为首要目标，由此催生了兼具年龄特异性与性别特异性的行为策略。本研究针对一种具有性体型二态性（sexual size dimorphism）的蜘蛛——筏蛛（raft spider，学名*Dolomedes fimbriatus*）展开了调查，该物种的雌性体型显著大于雄性。我们对从幼体至成体阶段的蜘蛛进行了重复观测，分析其大胆性、对猎物的贪食性以及攻击概率。研究结果显示，相较于雄性，雌性表现出更高的大胆性、更强的贪食性，以及更高的反击模拟攻击者的概率。值得注意的是，观测到的行为特征会随个体发育发生动态变化，且不同性别在行为变化的幅度与方向上均存在显著差异，这表明二者具备截然不同的生活史策略（life history strategies）……