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代价。我们以中华大刀螳（Tenodera sinensis）为实验对象，对这一假说进行了验证。实验中，我们为雌雄螳螂分别饲喂经不同放射性标记的蟋蟀，并允许其进行交配。其中半数交配组发生了性食同类行为，我们对另一半交配组则阻断了性食同类行为的发生。我们分别评估了雄性躯体物质与射精物质向雌性卵块与躯体的相对分配量。研究结果表明，雄性躯体投资可对子代产生做出贡献。发生性食同类的雌性，其卵块与生殖组织中含有的雄性源性氨基酸含量显著高于未发生性食同类的雌性；且性食同类行为发生后，雌性的产卵量有所提升。由此可见，性食同类可提升雄性对子代的物质投入。此外我们还发现，雄性亦可通过射精行为提供大量物质投入：即便未发生性食同类，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。