Sacoglossans, or “sap-sucking” sea slugs, are primarily algivorous, with many taxa exhibiting kleptoplasty, the feeding and retaining of photosynthetically active chloroplasts from algae. The Plakobranchus species complex exhibits some of the longest kleptoplast retention and survival times under starvation conditions, but the contributions of these kleptoplasts to their survival and overall fitness have been widely debated. In this study we assessed the effects of starvation and light on the fitness of Plakobranchus cf. ianthobaptus and its kleptoplasts by placing starved individuals in eight daily average light treatments, ranging from near dark (2 µmol photon m−2 s−1) to ambient light (470 µmol photon m−2 s−1). Slug weight was used as a metric of fitness, and kleptoplast photosynthetic activity was determined via maximum quantum yield (Fv/Fm) by pulse-amplitude modulated fluorometry as a proxy for kleptoplast health. Plakobranchus individuals in near-dark and high light treatments (>160 µmol photon m−2 s−1) experienced significantly greater weight loss than those in low light (65 µmol photon m−2 s−1) and moderate light treatments (95–135 µmol photon m−2 s−1). Additionally, individuals in high light treatments experienced a rapid decline in kleptoplast photosynthetic activity, while all other treatments experienced minimal decline. This relationship between kleptoplast degradation and weight loss suggests an important link between fitness and kleptoplasty. Given the significant negative effects of ambient conditions, regular refreshment and replenishment of kleptoplasts or physiological or behavioral adjustments are likely employed for the benefits of kleptoplasty to be maintained.

中文翻译：

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寻找最佳位置：亚环境光增加海蛞蝓 Plakobranchus 中的健康和 Kleptoplast 生存，参见。ianthobaptus Gould，1852 年

Sacoglossans，或“吸液”海蛞蝓，主要是食藻类，许多分类群表现出窃贼成形术，即从藻类中摄取和保留具有光合作用活性的叶绿体。Plakobranchus 物种复合体在饥饿条件下表现出一些最长的盗链体保留和存活时间，但这些盗链体对其生存和整体适应性的贡献已引起广泛争论。在这项研究中，我们评估了饥饿和光照对 Plakobranchus cf. 适应度的影响。ianthobaptus 及其盗链体通过将饥饿的个体置于八次平均日光处理中，范围从近乎黑暗（2 µmol 光子 m-2 s-1）到环境光（470 µmol 光子 m-2 s-1）。弹头重量被用作衡量健康的指标，和 kleptoplast 光合活性是通过最大量子产率 (Fv/Fm) 通过脉冲幅度调制荧光测定法确定的，作为 kleptoplast 健康的代表。Plakobranchus 个体在近暗和强光处理（>160 µmol 光子 m−2 s−1）中的体重减轻明显大于弱光（65 µmol 光子 m−2 s−1）和中等光照处理（95– 135 µmol 光子 m−2 s−1)。此外，高光处理的个体经历了 kleptoplast 光合活性的快速下降，而所有其他处理的下降幅度很小。kleptoplast 降解和体重减轻之间的这种关系表明健康和 kleptoplasty 之间存在重要联系。鉴于环境条件的显着负面影响，