Abstract：
In many animals, males increase their reproductive success by mating with as many females as possible. The number of females a male can fertilize is often limited by male competition for access to females, sperm competition, and the cost of sperm production. Especially, recent studies have shown that sperm production is more costly than previously expected. In the two-spotted spider mite, Tetranychus urticae Koch, the number of females a male can inseminate is limited mainly by male competition for access to females. However, in the absence of rivals, males mate with so many females that they can become sperm-depleted. Mating without sperm transfer does not produce any offspring, although it takes time and energy. Therefore, a question arises as to why males continue to mate even after sperm depletion. In this study, we hypothesized that males continue to mate because sperm is replenished after a short period. To test the hypothesis, we investigated how long it takes for sperm replenishment after sperm depletion. We found that in 3 h, sperm can be replenished enough to inseminate a few females. As 3 h is sufficiently short not to lose the next mating opportunity, the results support the hypothesis. However, copulation duration in the sperm-replenished males was significantly longer than in the sperm-depleted males but shorter than in males before sperm depletion. To explain the differences, further research would be necessary. In addition, anatomical physiology study in males is also required to confirm that sperm is indeed depleted and replenished.
摘要：
在许多动物中，雄性通过与尽可能多的雌性交配来提高繁殖成功率。雄性可以受精的雌性数量通常受到雄性争夺雌性的限制，精子竞争,以及精子生产的成本。尤其是,最近的研究表明，精子生产的成本比以前预期的要高。在两个斑点的蜘蛛螨中，荨麻疹科赫,男性可以授精的女性数量主要受到男性争夺女性的限制。然而,在没有对手的情况下,雄性与如此多的雌性交配，以至于它们会耗尽精子。没有精子转移的交配不会产生任何后代，虽然这需要时间和精力。因此,出现了一个问题，即为什么雄性即使在精子耗尽后仍继续交配。在这项研究中,我们假设雄性继续交配，因为精子在短时间内得到补充。为了检验假设，我们调查了精子耗尽后精子补充需要多长时间。我们发现在3小时内，可以补充足够的精子来给少数雌性授精。由于3小时足够短，不会失去下一次交配机会，结果支持这一假设。然而,补充精子的雄性的交配持续时间明显长于精子耗尽的雄性，但短于精子耗尽前的雄性。为了解释差异，进一步的研究将是必要的。此外,还需要对男性进行解剖学生理学研究，以确认精子确实已耗尽和补充。
