Data from: Spatial and temporal patterns of nest distribution influences sexual selection in a marine fish

In many species, the natural distribution of material resources important for reproduction can profoundly impact reproductive success among individuals and, hence, the opportunity and intensity of sexual selection. Here, we report on a field-based experiment investigating the effects of nest aggregation on sexual selection in a fish, the sand goby (Pomatoschistus minutus). We found that the distribution of potential nests (sparse versus aggregated nest treatments) affected patterns of nest colonization and reproductive success. Specifically, in the treatment with aggregated nesting resources, a greater proportion of nests remained unoccupied by sand goby males. Although the size of nesting males did not differ between treatments, eggs accumulated more rapidly when nests were sparsely distributed. We found that the opportunity for selection decreased over time with the accumulation of eggs in the nests in both the aggregated and sparse treatments. Moreover, the effect of male size on reproductive success was influenced by an interaction between nest distribution and time, with the selection gradient being highest right after nest colonization when nests were aggregated, while the opposite pattern was observed in the sparse nest treatment. Such findings highlight the vital role that environmental and social factors can play in determining the importance of male phenotypic traits (in this case, male size). More broadly, our results also underscore how the natural distribution of resources, both in space and time, can impact the strength of sexual selection acting on wild animal populations.

在诸多物种中，对繁殖至关重要的物质资源的自然分布格局，会深刻影响个体间的繁殖成功率，进而影响性选择的机会与强度。
本研究针对一种鱼类——沙𫚥虎（Pomatoschistus minutus），开展野外实验，探究巢址聚集格局对其性选择的影响。
研究结果显示，潜在巢址的分布格局（稀疏巢处理组与聚集巢处理组）会影响巢址定居模式与繁殖成功率。具体而言，在巢址资源聚集的处理组中，未被沙𫚥虎雄性个体占据的巢址比例更高。尽管两组处理中筑巢雄性的体型并无显著差异，但当巢址呈稀疏分布时，卵的积累速度更快。
我们发现，无论是聚集组还是稀疏组，随着巢内卵的积累，性选择机会均随时间推移而降低。此外，雄性体型对繁殖成功率的影响受巢址分布与时间的交互作用调控：在巢址聚集的处理组中，选择梯度在巢址刚完成定居时达到峰值；而稀疏巢处理组则呈现相反的变化模式。
上述研究结果凸显了环境与社会因素在决定雄性表型性状（本研究中为雄性体型）的重要性方面所发挥的关键作用。从更广泛的视角来看，本研究结果也阐明了资源在空间与时间维度上的自然分布格局，如何影响野生动物种群所承受的性选择强度。