Data from: Male-female coevolution in the wild: evidence from a time series in Artemia franciscana

Sexual conflicts are ubiquitous in nature and are expected to lead to an antagonistic coevolution between the sexes. This coevolutionary process is driven by selection on sexually antagonistic traits that can either be directional or fluctuating. In this study, we used dormant cysts of Artemia franciscana, collected in the same population in three different years over a 23-year period (corresponding to ~160 generations in this system), to investigate male-female coevolution in natural conditions over time. We performed a cross experiment study where reproduction of females mated to males from the past, present or future was monitored until death. In agreement with a model of ‘fluctuating selection’, we found that females survived better and had longer interbrood intervals when mated with their contemporary males compared to when mated with males from the future or the past. However, female weekly and lifetime reproductive successes displayed no differences between contemporary and non-contemporary matings. Finally, the coevolutionary patterns (‘arms race dynamics’ or ‘fluctuating selection dynamics’) possibly acting on female relative fitness could not be discriminated. This study is the first direct demonstration that the process of male – female coevolution, previously revealed by experimental evolution in laboratory artificial conditions, can occur in nature on a short evolutionary time scale.

性冲突在自然界中普遍存在，并被认为会导致两性间的拮抗共进化（antagonistic coevolution）。该共进化过程由作用于性拮抗性状（sexually antagonistic traits）的选择压力驱动，这类选择可分为定向选择与波动选择两类。本研究以23年间（对应该实验体系约160个世代）从同一种群采集的丰年虫（Artemia franciscana）休眠孢囊（dormant cysts）为实验材料，探究自然条件下随时间推移的雌雄共进化动态。我们开展了跨世代交配实验，持续监测与过去、当前或未来雄性交配的雌性直至其死亡的繁殖表现。结果与"波动选择"模型的预测相符：相较于与未来或过去雄性交配的雌性，与同期雄性交配的雌性存活率更高，育幼间隔更长。然而，雌性的周繁殖成功率与终生繁殖成功率在同期与非同期交配组合间并无显著差异。最终，我们无法区分作用于雌性相对适合度的共进化模式究竟属于"军备竞赛动态"还是"波动选择动态"。本研究首次直接证实：此前仅在实验室人工条件下通过实验进化研究揭示的雌雄共进化过程，可在自然环境中以较短的进化时间尺度发生。