Evolutionary Biology and Ecology, Université Libre de Bruxelles, Brussels, Brussels B-1050, Belgium.
Proc Biol Sci. 2023 Mar 29;290(1995):20230216. doi: 10.1098/rspb.2023.0216.
Sperm competition is a pervasive evolutionary force that shapes sperm traits to maximize fertilization success. Indeed, it has been shown to increase sperm production in both vertebrates and invertebrates. However, sperm production is energetically costly, which may result in trade-offs among sperm traits. In eusocial hymenopterans, such as ants, mating dynamics impose unique selective pressures on ejaculate. Males are sperm limited: they enter adulthood with a fixed amount of sperm that will not be renewed. We explored whether sperm competition intensity was associated with sperm quantity and quality (i.e. sperm viability and DNA fragmentation) in nine desert ants. Our results provide phylogenetically robust evidence that sperm competition is positively correlated with sperm production and sperm viability. However, it was unrelated to sperm DNA integrity, indicating the absence of a trade-off involving this trait. These findings underscore that sperm competition may strongly mould sperm traits and drive reproductive performance in eusocial Hymenoptera.
精子竞争是一种普遍存在的进化力量，它塑造了精子的特征，以最大限度地提高受精成功的机会。事实上，已经有研究表明，它会增加脊椎动物和无脊椎动物的精子产量。然而，精子的产生是需要消耗能量的，这可能会导致精子特征之间产生权衡。在真社会性膜翅目昆虫中，如蚂蚁，交配动态对精液施加了独特的选择压力。雄性精子有限：它们进入成年期时携带的精子数量是固定的，不会再增加。我们在 9 种沙漠蚂蚁中探索了精子竞争的强度是否与精子数量和质量（即精子活力和 DNA 碎片化）有关。我们的研究结果提供了系统发育稳健的证据，表明精子竞争与精子产生和精子活力呈正相关。然而，它与精子 DNA 的完整性无关，表明不存在涉及该特征的权衡。这些发现强调了精子竞争可能会强烈塑造真社会性膜翅目昆虫的精子特征，并驱动其繁殖性能。
