Data from: The shield effect: nuptial gifts protect males against precopulatory sexual cannibalism

Several not mutually exclusive functions have been ascribed to nuptial gifts across different taxa. Although the idea that a nuptial prey gift may protect the male from pre-copulatory sexual cannibalism is attractive, it has previously been considered of no importance based on indirect evidence and rejected by experimental tests. We reinvestigated whether nuptial gifts may function as a shield against female attacks during mating encounters in the spider Pisaura mirabilis and whether female hunger influences the likelihood of cannibalistic attacks. The results showed that pre-copulatory sexual cannibalism was enhanced when males courted without a gift and this was independent of female hunger. We propose that the nuptial gift trait has evolved partly as a counteradaptation to female aggression in this spider species.

跨多个动物类群，学界已为婚赠礼物（nuptial gifts）归为数种非互斥的功能。尽管“以猎物作为婚赠可保护雄性免受交配前性食同类行为侵害”这一假说颇具吸引力，但此前基于间接证据被认为无足轻重，且经实验检验后遭到否定。我们针对两个问题再度开展探究：其一，在奇异狡蛛（Pisaura mirabilis）的交配互动中，婚赠礼物是否可作为盾牌抵御雌性的攻击；其二，雌性的饥饿状态是否会影响性食同类行为的发生概率。实验结果显示，雄性在无礼物求偶时，交配前性食同类行为的发生概率显著升高，且该现象与雌性的饥饿状态无关。我们提出，该蜘蛛物种的婚赠性状的演化，部分是作为对抗雌性攻击行为的反适应策略。