Much empirical data obtained across taxa is necessary to evaluate how variation in migratory costs and benefits can play a role in shaping the phenotypic and genetic patterns of reproductive investment between populations. Reproductive resources are allocated to both the size and number of eggs, and females may vary their allocation to each of these traits in response to increased movement capacity. In central regions of Japan, the rice plant skipper Parnara guttata guttata migrates in a southwesterly direction every year during late summer and early autumn (‘migratory’ population), but this migration is not observed in populations in southern or parts of western Japan (‘resident’ population). If migratory costs and benefits vary between these populations, they may cause their reproductive strategies to differ. Moreover, migration combined with a shift of reproductive allocation that evolved in one generation may influence the flight ability and patterns of reproductive allocation in the other generation in which migration has not evolved. In this study, a common-garden experiment was conducted to compare reproductive traits (egg size and number of eggs), flight ability and body size between these populations under two daylength regimes, at which different forms of adult P. g. guttata emerge. Under both daylength regimes the female adults of migratory populations had greater flight ability and tended to lay a greater number of eggs, which were on average smaller than the eggs laid by resident population females. A population-level difference in reaction norm elevation for flight ability and number of eggs was detected, but no interactions between population and daylength. The effects of the energetic cost of flight, adaptive constraints (e.g., genetic correlations and trade-offs), and the optimal strategy may explain the difference between populations of this species in the patterns of reproductive allocation to egg size and number of eggs.

为了评估迁徙成本和收益的变化如何在塑造人口之间的生殖投资的表型和遗传模式中发挥作用，需要从整个分类单元获得许多经验数据。生殖资源被分配给鸡蛋的大小和数量，雌性可能会随着运动能力的增加而改变对每种性状的分配。在日本中部地区，稻农船长Parnara guttata guttata每年夏末和初秋期间（“迁徙”人口）每年都向西南方向迁移，但在日本南部或西部部分地区（“居民”人口）中没有观察到这种迁移。如果这些人群之间的迁徙成本和收益不同，则可能导致其生殖策略不同。此外，移徙与一代人进化的生殖配置转移相结合，可能会影响另一代未进化的人口的飞行能力和生殖分配模式。在这项研究中，进行了一个普通的花园实验，以比较在两种日间长势下这些种群之间的生殖性状（蛋的大小和卵的数量），飞行能力和体型，在这种情况下，成年的P. g。古塔塔出现。在两种日间制度下，移徙种群的成年雌鸟都有较大的飞行能力，并倾向于产下更多的卵，这些卵平均比常住种群的雌性产卵小。检测到了反应水平对飞行能力和卵数的反应的种群水平差异，但种群与日长之间没有相互作用。高能飞行成本，适应性限制（例如遗传相关性和权衡）以及最佳策略的影响可以解释该物种种群在生殖分配模式中对卵大小和卵数的差异。