Sperm digestion and reciprocal sperm transfer can drive hermaphrodite sex allocation to equality
Sperm digestion and reciprocal sperm transfer can drive hermaphrodite sex allocation to equality
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DOI：
10.1086/303184
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发表时间：
1999-04-01
影响因子：
2.9
通讯作者：
Michiels, NK
中科院分区：
文献类型：
--
作者：
Greeff, JM;Michiels, NK
精子竞争的激烈程度决定了应该在精子上投入多少生殖努力。影响精子竞争的一个重要因素是雌性的交配频率，因为它决定了射精之间的竞争程度。在同时发生的雌雄同体中，花在精子上的能量必须与花在卵子生产上的能量进行权衡。通过扩展现有的模型，我们考虑如何交配的数量影响精子的竞争，因此，性别分配在内部同步雌雄同体。然后，我们继续探讨两性交配系统的两个共同特征，即精子消化和相互授精的后果。由于精子消化降低了给定射精的竞争能力，它选择增加精子投资。因此，被消化的精子数量和雄性分配可以进入一个共同进化的循环，在这个循环中，两者都会增加到对雄性和雌性配子的投资相等的程度，并且消化率很高。由于精子的高度消化，通过雄性功能的适应性变得更依赖于在精子上投入的资源的数量，而不是交配的数量。因此，精子消化减少贝特曼原则。因此，具有精子消化能力的雌雄同体应该不太可能表现出增加交配次数的特征。一旦射精量大且成本高，坚持相互精子移植的动物将受到青睐，因为它们的投资得到了一些补偿。在互惠的情况下，对精子的投资甚至更高。这是由于伴侣的射精和通过增加伴侣的卵子产量而获得的婚姻礼物效应的补偿。
The intensity of sperm competition determines how much reproductive effort should be invested in sperm. One important factor affecting sperm competition in internally fertilizing organisms is the mating frequency of females, since it determines the extent of competition between ejaculates. In simultaneous hermaphrodites, energy spent on sperm has to be traded off against energy expended on ova production. By extending an existing model, we consider how the number of matings affects sperm competition and, thus, sex allocation in internally fertilizing simultaneous hermaphrodites. We then go on to explore the consequences of two common characteristics of hermaphroditic mating systems, namely, sperm digestion and reciprocal insemination. Since sperm digestion reduces the competitive ability of a given ejaculate, it selects for increased sperm investment. As a result, the amount of sperm digested and male allocation can enter a coevolutionary cycle in which both will increase up to the point of equal investment in male and female gametes and in high rates of digestion. Because of this high degree of sperm digestion, fitness through the male function becomes more dependent on the amount of resources invested in sperm than on the number of matings. As a result, sperm digestion reduces Bateman's principle. Hence, hermaphrodites with sperm digestion should be less likely to display traits that increase the number of matings. Once ejaculates are large and costly, animals insisting on reciprocal sperm transfer will be favored since they receive some compensation for their investment. Under reciprocity, an even higher investment in sperm is favored. This is the result of the compensation received in the form of the partner's ejaculate and a nuptial gift effect by increasing a partner's production of eggs.