Data from: Intergenerational paternal effect of adult density in Drosophila melanogaster

1. Notwithstanding recent evidences, paternal environment is thought to be a potential but unlikely source of fitness variation that can affect trait evolution. Here we studied intergenerational effects of males' exposure to varying adult density in Drosophila melanogaster laboratory populations. 2. We held sires at normal (N), medium (M) and high (H) adult densities for two days before allowing them to mate with virgin females. This treatment did not introduce selection through differential mortality. Further, we randomly paired males and females and allowed a single round of mating between the sires and the dams. We then collected eggs from the dams and measured the egg size. Finally, we investigated the effect of the paternal treatment on juvenile and adult (male) fitness components. 3. We found a significant treatment effect on juvenile competitive ability where the progeny sired by the H-males had higher competitive ability. Since we did not find the treatment to affect egg size, this effect is unlikely to be mediated through variation in female provisioning. 4. Male fitness components were also found to have a significant treatment effect: M-sons had lower dry weight at eclosion, higher mating latency and lower competitive mating success. 5. While being the first study to show both adaptive and non-adaptive effect of the paternal density in Drosophila, our results highlight the importance of considering paternal environment as important source of fitness variation.

1. 尽管已有近期相关研究证据，父本环境仍被视为一种潜在却可能性较低的、可影响性状演化（trait evolution）的适合度变异（fitness variation）来源。本研究以实验室种群的黑腹果蝇（Drosophila melanogaster）为实验材料，探究雄性成虫暴露于不同成虫密度下的跨代遗传效应。
2. 我们将父本雄性分别置于正常（N）、中等（M）与高（H）成虫密度环境中饲养2天，随后使其与处女雌蝇交配。该处理未通过差异化死亡率引入选择压力。此外，我们采用随机配对的方式组合雌雄个体，仅开展一轮交配。随后收集雌蝇所产的卵并测量其大小。最终，我们分析了父本处理对子代幼体及成体（雄性）适合度组分（fitness components）的影响。
3. 研究发现，父本处理对子代竞争能力（competitive ability）存在显著影响：高密组（H组）父本所产子代的竞争能力更强。由于未观察到处理对卵大小产生影响，该效应不太可能通过雌亲的子代营养供给（female provisioning）差异介导产生。
4. 雄性子代的适合度组分同样呈现显著处理效应：中等密度组（M组）的雄性子代在羽化时干重（dry weight at eclosion）更低、交配潜伏期（mating latency）更长，且交配竞争成功率（competitive mating success）更低。
5. 本研究首次在黑腹果蝇中证实了父本密度所介导的适应性与非适应性效应（adaptive and non-adaptive effect），研究结果凸显了将父本环境作为适合度变异重要来源加以考量的必要性。