Data from: The lek mating system of the worm pipefish (Nerophis lumbriciformis): a molecular maternity analysis and test of the phenotype-linked fertility hypothesis

The origin and maintenance of mating preferences continues to be an important and controversial topic in sexual selection research. Leks and lek-like mating systems, where individuals gather in particular spots for the sole purpose of mate choice, are particularly puzzling, because the strong directional selection imposed by mate choice should erode genetic variation among competing individuals and negate any benefit for the choosing sex. Here, we take advantage of the lek-like mating system of the worm pipefish (Nerophis lumbriciformis) to test the phenotype-linked fertility hypothesis for the maintenance of mating preferences. We use microsatellite markers to perform a parentage analysis, along with a mark-recapture study, to confirm that the worm pipefish has an unusual mating system that strongly resembles a female lek, where females display and males visit the lek to choose mates. Our results show that the most highly ornamented females occupy positions near the centre of the breeding area, and males mating with these females receive fuller broods with larger eggs compared to males mating with less ornamented females. We also conduct a laboratory experiment to show that female ornaments are condition dependent and honestly signal reproductive potential. Overall, these results are consistent with the predictions of a sex-independent version of the phenotype-linked fertility hypothesis, as male preference for female ornaments correlates with fertility benefits.配偶偏好的起源与维持，始终是性选择研究领域兼具重要性与争议性的核心议题。求偶场（lek）及类求偶场交配系统，指个体仅为完成配偶选择而聚集于特定区域的交配体系，此类系统尤为令人困惑：因为配偶选择所施加的强定向选择，本应削弱竞争个体间的遗传变异，并抵消选择性别所能获得的任何收益。 本研究以虫纹海龙（Nerophis lumbriciformis）的类求偶场交配系统为研究模型，旨在检验配偶偏好维持的表型关联生育力假说（phenotype-linked fertility hypothesis）。研究团队通过微卫星标记（microsatellite marker）开展亲权分析（parentage analysis），并结合标记重捕研究（mark-recapture study），证实虫纹海龙拥有一种极似雌性求偶场的特殊交配系统：雌性个体在此展示自身特质，雄性则到访求偶场完成配偶选择。 研究结果显示，体表装饰最为发达的雌性会占据繁殖区域中心附近的位置；与这类雌性交配的雄性，其育儿囊内的卵团更为饱满、卵粒尺寸也更大，相较与装饰程度较低的雌性交配的雄性而言。此外本研究还开展了室内控制实验，证实雌性的体表装饰存在条件依赖性，并能真实传递其繁殖潜力。 综上，本研究结果与表型关联生育力假说的性别独立版本预测相符——雄性对雌性体表装饰的偏好，与其所获得的生育收益呈显著正相关。