Data from: Energy and lipid metabolism during direct and diapause development in a pierid butterfly

Diapause is a fundamental component of the life-cycle in the majority of insects living in environments characterized by strong seasonality. The present study addresses poorly understood associations and trade-offs between endogenous diapause duration, thermal sensitivity of development, energetic cost of development and cold tolerance. Diapause intensity, metabolic rate trajectories and lipid profiles of directly developing and diapausing animals were studied using pupae and adults of Pieris napi butterflies from a population for which endogenous diapause is well studied. Endogenous diapause was terminated after 3 months and termination required chilling. Metabolic and postdiapause development rates increased with diapause duration, while the metabolic cost of postdiapause development decreased, indicating that once diapause is terminated development proceeds at a low rate even at low temperature. Diapausing pupae had larger lipid stores than the directly developing pupae and lipids constituted the primary energy source during diapause. However, during diapause lipid stores did not decrease. Thus, despite lipid catabolism meeting the low energy costs of the diapausing pupae, primary lipid store utilization did not occur until the onset of growth and metamorphosis in spring. In line with this finding, diapausing pupae contained low amounts of mitochondria-derived cardiolipins, which suggests a low capacity for fatty acid β-oxidation. While ontogenic development had a large effect on lipid and fatty acid profiles, only small changes in these were seen during diapause. The data therefore indicate that the diapause lipidomic phenotype is built early, when pupae are still at high temperature, and retained until diapause post-diapause development.

滞育（Diapause）是多数栖息于强季节性环境中的昆虫生命周期的核心环节。本研究针对目前尚不明晰的内源性滞育（endogenous diapause）时长、发育热敏感性、发育能量成本与耐寒性之间的关联与权衡关系展开探讨。本研究以一个内源性滞育特性已被充分解析的菜粉蝶（Pieris napi）种群的蛹与成虫为实验材料，对直接发育个体与滞育个体的滞育强度、代谢速率轨迹及脂质谱（lipid profiles）特征进行了研究。研究结果显示，内源性滞育会在3个月后终止，且终止过程需伴随低温刺激。代谢速率与滞后发育速率随滞育时长的延长而升高，而滞后发育的代谢成本则随之降低，这表明一旦滞育终止，即便处于低温环境，发育也会以较低速率推进。滞育蛹的脂质储备量高于直接发育的蛹，且脂质是滞育期间的主要能量来源。但滞育期间脂质储备并未出现消耗。由此可见，尽管脂质分解代谢可满足滞育蛹的低能量需求，但脂质储备的主要动用并未发生，直至春季生长与变态阶段才会启动。与此发现相符的是，滞育蛹的线粒体源性心磷脂（cardiolipins）含量较低，这提示其脂肪酸β-氧化能力较弱。尽管个体发育对脂质与脂肪酸谱具有显著影响，但滞育期间此类谱仅出现微小变化。综上，本研究数据表明，滞育脂质组学表型（lipidomic phenotype）在蛹仍处于高温环境时便已形成，并将持续保留至滞后发育阶段。