Data from: Sexual cannibalism increases male material investment in offspring: quantifying terminal reproductive effort in a praying mantis

Models of the evolution of sexual cannibalism argue that males may offset the cost of cannibalism if components of the male body are directly allocated to the eggs that they fertilize. We tested this idea in the praying mantid Tenodera sinensis. Males and females were fed differently radiolabelled crickets and allowed to mate. Half of the pairs progressed to sexual cannibalism and we prevented cannibalism in the other half. We assess the relative allocation of both male-derived somatic materials and ejaculate materials into the eggs and soma of the female. Our results show that male somatic investment contributes to production of offspring. The eggs and reproductive tissues of cannibalistic females contained significantly more male-derived amino acids than those of non-cannibalistic females, and there was an increase in the number of eggs produced subsequent to sexual cannibalism. Sexual cannibalism thus increases male material investment in offspring. We also show that males provide substantial investment via the ejaculate, with males passing about 25% of their radiolabelled amino acids to females via the ejaculate even in the absence of cannibalism.

性食同类（sexual cannibalism）的演化模型指出，若雄性躯体组分可直接分配至其所受精的卵中，雄性或可抵消性食同类行为带来的适应性代价。我们以中华大刀螳（Tenodera sinensis）为实验对象验证这一假说：为雌雄个体喂食经不同放射性标记的蟋蟀，并允许其交配。其中半数交配组合发生了性食同类行为，另一半则通过人为干预阻止了性食同类的发生。我们评估了雄性来源的体细胞物质与射精物质向雌性卵组织及躯体的相对分配情况。研究结果表明，雄性体细胞投资可对子代生产作出贡献：性食同类雌性的卵与生殖组织中，雄性来源氨基酸的含量显著高于非性食同类雌性，且性食同类行为发生后，雌性的产卵数量有所增加。由此可见，性食同类行为可提升雄性对子代的物质投入总量。我们还发现，雄性可通过射精途径提供大量物质投资：即使未发生性食同类行为，雄性仍可通过射精将约25%的放射性标记氨基酸传递给雌性。