Data from: Adult sex ratio and operational sex ratio exhibit different temporal dynamics in the wild

Adult sex ratio (ASR, the proportion of adult males in the adult population) and operational sex ratio (OSR, the proportion of sexually active males in the mating pool) are fundamental properties of breeding populations and they are often linked to mating systems and sexual selection. However, ASR and OSR emerge via different routes in a population and may exhibit different temporal patterns. Here, we use data from a well-monitored polygamous snowy plover Charadrius nivosus population sampled over 3 consecutive breeding seasons to investigate whether temporal changes in ASR relate to changes in OSR. We found that snowy plovers exhibited male-biased ASR and OSR. Consistent with theoretical expectations, OSR was more variable than ASR. However, there was no consistent relationship between OSR and ASR: in only 1 of the 3 study years we found a weak positive relationship (r = 0.22). The lack of association was corroborated by time series analyses and sensitivity tests. Our work therefore suggests that ASR and OSR exhibit different temporal patterns in a polygamous population, and we call for further theoretical and empirical studies that analyze their relationship across a range of different breeding systems.

成体性比（Adult sex ratio, ASR，即成体种群中成体雄性的占比）与有效交配性比（operational sex ratio, OSR，即交配池中性活跃雄性的占比）是繁殖种群的核心基本属性，二者通常与婚配制度及性选择存在密切关联。然而，成体性比与有效交配性比的种群形成路径存在差异，且可能呈现不同的时间动态模式。本研究依托连续3个繁殖季对多配制雪鸻（Charadrius nivosus）种群的标准化监测数据，探究成体性比的时间变化是否与有效交配性比的变化存在关联。研究结果显示，雪鸻种群的成体性比与有效交配性比均表现为雄性偏倚；与理论预期相符，有效交配性比的波动幅度大于成体性比。但二者并未呈现稳定的相关关系：仅在3个研究年份中的1个年份观测到微弱的正相关（r=0.22）。时间序列分析与敏感性检验进一步佐证了这一无关联的结论。综上，本研究表明在多配制种群中，成体性比与有效交配性比呈现不同的时间动态模式，同时呼吁学界开展更多覆盖不同婚配制度的理论与实证研究，以深入解析二者的关联机制。