Data from: Does selection on increased cold tolerance in the adult stage confer resistance throughout development?

Artificial selection is a powerful approach to unravel constraints on genetic adaptation. While it has been frequently used to reveal genetic trade-offs among different fitness-related traits, only a few studies have targeted genetic correlations across developmental stages. Here we test whether selection on increased cold tolerance in the adult stage increases cold resistance throughout ontogeny in the butterfly Bicyclus anynana. We used lines selected for decreased chill-coma recovery time and according controls, which had originally been set up from three levels of inbreeding (outbred control, one or two full-sib matings). Four generations after having terminated selection, a significant response to selection was found in one day-old butterflies (the age at which selection took place). Older adults showed a very similar though weaker response. Nevertheless, cold resistance did not increase in either egg, larval or pupal stage in the selection lines, but was even lower compared to control lines for eggs and young larvae. These findings suggest a cost of increased adult cold tolerance, presumably reducing resource availability for offspring provisioning and thereby stress tolerance during development, which may substantially affect evolutionary trajectories.

人工选择（artificial selection）是解析遗传适应（genetic adaptation）约束机制的有效途径。尽管该方法常被用于揭示不同适合度相关性状（fitness-related traits）间的遗传权衡（genetic trade-offs），但仅有少数研究聚焦于不同发育阶段间的遗传相关性。本研究以蝶类Bicyclus anynana为实验对象，探究成虫阶段针对耐寒性（cold tolerance）提升的选择是否会提升其整个个体发育（ontogeny）全程的耐寒能力。我们使用了经选择获得的冷昏迷恢复时间（chill-coma recovery time）缩短的品系及其对应对照品系，这些品系最初由三个近交（inbreeding）水平构建：远交对照（outbred control）、一次全同胞交配（full-sib matings）或两次全同胞交配（full-sib matings）。在选择实验终止后的第四代，我们在1日龄成虫（即选择实验实施时的虫龄）中观测到了显著的选择响应，日龄更大的成虫也呈现出相似但更弱的选择响应。然而，选择品系的卵、幼虫及蛹阶段均未出现耐寒能力提升，且卵与早期幼虫的耐寒能力甚至低于对照品系。上述结果表明，成虫耐寒性提升存在适合度代价：这可能会减少用于子代营养供给的资源，进而降低发育过程中的胁迫耐受能力，最终可能对进化轨迹（evolutionary trajectories）产生显著影响。