Male medaka continue to mate with females despite sperm depletion

In animals where males engage in multiple matings, sperm depletion can substantially reduce the reproductive success of both sexes. However, little is known about how successive matings affect sperm depletion, fertilisation rates, and mating behaviour. Here, we investigated this phenomenon under laboratory conditions. Medaka (Oryzias latipes), an externally fertilising fish, is an ideal model to test predictions of sperm depletion because there are established methods to observe its mating and count sperm. Medaka males mated with multiple females (19 per day, on average; range, 4–27), experiencing significant sperm depletion, with sperm release declining markedly after the first few matings, reaching only 0.5–6.3% by the last mating of the day. Fertilisation rates decreased, particularly after approximately 10 consecutive matings, although there was some recovery in the next-day’s matings. The decline in courtship effort and mating duration probably resulted from the males becoming incr..., , , # Data from: Male medaka continue to mate with females despite sperm depletion

[https://doi.org/10.5061/dryad.h18931zvs](https://doi.org/10.5061/dryad.h18931zvs)

Data on male medaka (*Oryzias latipes*) reproductive limits, examining mating behavior until exhaustion by presenting fertile females. The experiment used medaka (himedaka) maintained at Osaka Metropolitan University, Japan.

Contact Yuki Kondo ([[e-mail]](mailto:[e-mail])) with any questions. This manuscript has been accepted for publication (11/26/2024).

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在雄性存在多次交配行为的动物类群中，精子枯竭会显著降低两性的繁殖成功率。然而目前学界对连续交配如何影响精子枯竭、受精率及交配行为的认知仍较为有限。本研究在实验室条件下对该现象展开了探究。

青鳉（*Oryzias latipes*）是体外受精的鱼类，是验证精子枯竭相关预测的理想模型，因其交配观察与精子计数方法已较为成熟。

青鳉雄性会与多尾雌性进行交配（平均每日19次，范围4~27次），会出现显著的精子枯竭现象：交配前几次后精子释放量即出现明显下降，当日最后一次交配时仅为初始的0.5%~6.3%。受精率随交配次数增加而下降，尤其是在连续约10次交配后，不过次日的交配行为中受精率有所恢复。求偶投入与交配时长的下降可能源于雄性的……

# 数据源自：《雄性青鳉尽管精子枯竭仍会继续与雌性交配》
DOI: https://doi.org/10.5061/dryad.h18931zvs

本数据集包含雄性青鳉（*Oryzias latipes*）的繁殖极限相关数据，通过向雄性提供可育雌性，记录其直至交配耗尽时的交配行为。实验所用青鳉（俗称himedaka）饲养于日本大阪都市大学。

如有疑问，请联系近藤由纪（Yuki Kondo），邮箱：[e-mail]。本稿件已于2024年11月26日被接收待刊。

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