In polygamous species, the mode of sperm storage in females influences evolution of sperm quantitative and qualitative traits because it provides the arena for sperm competition, cryptic female choice and fertilization processes. In this study, we compared ejaculate traits of two squid species, Heterololigo bleekeri and Loligo reynaudii. Both species show dimorphic sperm traits associated with alternative reproductive tactics where consort and sneaker males transfer sperm to different storage sites within a female (on the oviduct and near the mouth, respectively). Due to differences in reproductive behaviours and sperm placement, sperm competition risk is expected to be higher in sneakers than in consorts of both species and higher overall in L. reynaudii. Our results demonstrate that the instantaneous number of released sperm is adjusted to the expected sperm competition risk via an elaborate sperm package. Consort sperm are similar in size; however, sneaker sperm have a significantly longer flagellum in H. bleekeri than in L. reynaudii, most likely due to intra-tactic conflicts associated with sperm storage conditions. From consideration of the different mating tactics, we suggest that while levels of sperm competition determine quantitative traits, sperm quality traits are determined more by the mode of sperm storage and fertilization.

中文翻译：

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精子竞争风险影响精子数量的射精策略，但不会影响鱿鱼的精子大小。

在一夫多妻的物种中，雌性精子的储存方式影响精子数量和质量特征的进化，因为它为精子竞争、神秘的雌性选择和受精过程提供了场所。在本研究中，我们比较了两种鱿鱼 Heterololigo bleekeri 和 Loligo reynaudii 的射精特性。这两个物种都显示出与替代生殖策略相关的双态精子特征，配偶和运动鞋男性将精子转移到女性体内的不同储存部位（分别在输卵管和嘴附近）。由于生殖行为和精子位置的差异，运动鞋中的精子竞争风险预计高于两个物种的配偶，而雷诺兹的整体精子竞争风险更高。我们的结果表明，通过精心设计的精子包，释放的精子的瞬时数量可以根据预期的精子竞争风险进行调整。配偶精子大小相似；然而，运动鞋精子在 H. bleekeri 中的鞭毛明显长于 L. reynaudii，这很可能是由于与精子储存条件相关的内部策略冲突。考虑到不同的交配策略，我们认为虽然精子竞争水平决定数量性状，但精子质量性状更多地取决于精子储存和受精的方式。很可能是由于与精子储存条件相关的内部策略冲突。考虑到不同的交配策略，我们认为虽然精子竞争水平决定数量性状，但精子质量性状更多地取决于精子储存和受精的方式。很可能是由于与精子储存条件相关的内部策略冲突。考虑到不同的交配策略，我们认为虽然精子竞争水平决定数量性状，但精子质量性状更多地取决于精子储存和受精的方式。