Fernlund Isaksson Erika, Fitzpatrick John L
Department of Zoology, Stockholm University, Stockholm, Sweden.
J Evol Biol. 2023 Apr;36(4):709-719. doi: 10.1111/jeb.14166. Epub 2023 Mar 9.
Sexually selected traits can be costly to produce and maintain. The amount of resources available to an individual is therefore expected to influence investment in costly sexual traits. While resource-dependent expression of sexually selected traits has traditionally been examined in males, resource limitation can also influence how sexual selection operates in females. Female reproductive fluids are thought to be costly to produce and may play an important role in shaping the outcome of postcopulatory sexual selection by influencing sperm performance. However, we know surprisingly little about whether and how female reproductive fluids are influenced by resource limitation. Here, we examine if resource restriction influences female reproductive fluid-sperm interactive effects in the pygmy halfbeak (Dermogenys collettei), a small internally fertilizing freshwater fish where females store sperm. After experimentally altering female diets (high vs. restricted diets), we compared how female reproductive fluids influence two key metrics of sperm quality: sperm viability and velocity. While female reproductive fluids enhanced sperm viability and velocity, we found no evidence that female diet influenced the interactive effect between female reproductive fluids and sperm viability or velocity. Our findings build on the growing evidence that female reproductive fluids influence sperm performance and call for further attention to be devoted to understanding how resource quantity and quality influence how female reproductive fluids affect sperm performance.
性选择特征的产生和维持可能代价高昂。因此，预计个体可获得的资源量会影响对代价高昂的性特征的投入。虽然传统上在雄性中研究了性选择特征对资源的依赖性表达，但资源限制也会影响雌性的性选择运作方式。雌性生殖液被认为生产成本高昂，并且可能通过影响精子性能在塑造交配后性选择的结果中发挥重要作用。然而，令人惊讶的是，我们对雌性生殖液是否以及如何受到资源限制的影响知之甚少。在这里，我们研究了资源限制是否会影响侏儒半颌鱼（Dermogenys collettei）中雌性生殖液与精子的相互作用，侏儒半颌鱼是一种小型体内受精的淡水鱼，雌性会储存精子。在通过实验改变雌性的饮食（高营养饮食与受限饮食）后，我们比较了雌性生殖液如何影响精子质量的两个关键指标：精子活力和速度。虽然雌性生殖液提高了精子活力和速度，但我们没有发现证据表明雌性饮食会影响雌性生殖液与精子活力或速度之间的相互作用。我们的研究结果建立在越来越多的证据基础上，即雌性生殖液会影响精子性能，并呼吁进一步关注资源的数量和质量如何影响雌性生殖液对精子性能的影响。
