n-3 polyunsaturated fatty acids (n-3 PUFAs), including eicosapentaenoic acid (EPA), are essential nutrients for vertebrate development and physiology. Microorganisms, such as microalgae, produce n-3 PUFAs that are transferred to higher predators in the aquatic food web. However, recent studies have demonstrated that various aquatic invertebrates possess the biosynthetic enzymes required for n-3 PUFA production, raising the possibility that n-3 PUFAs are also produced in certain aquatic invertebrates. In contrast to aquatic invertebrates, it remains unclear whether and how PUFAs are produced in terrestrial invertebrates, including collembolans, one of the most widespread microarthropods in soil ecosystems. In this study, we investigated the biosynthetic capacity of n-3 PUFAs in litter-dwelling Collembola, Sinella dubiosa. We detected EPA in Sinella dubiosa reared on Brewer's yeast, which produced only saturated and monounsaturated fatty acids. Furthermore, metabolic analysis using isotope-labeled fatty acids revealed that oleic, linolenic, and arachidonic acids were metabolized to EPA in Sinella dubiosa. Given that collembolans are food for predatory arthropods and their nutrients are transferred to higher predatory vertebrates in the soil food web, we propose that Collembola serve as an EPA source in soil ecosystems.

n-3 多不饱和脂肪酸 (n-3 PUFA)，包括二十碳五烯酸 (EPA)，是脊椎动物发育和生理的必需营养素。微生物，如微藻，产生 n-3 PUFA，并转移给水生食物网中的高级捕食者。然而，最近的研究表明，各种水生无脊椎动物拥有生产 n-3 PUFA 所需的生物合成酶，这增加了某些水生无脊椎动物也生产 n-3 PUFA 的可能性。与水生无脊椎动物相比，目前尚不清楚陆生无脊椎动物是否以及如何产生多不饱和脂肪酸，包括弹跳虫，土壤生态系统中最广泛分布的微型节肢动物之一。在本研究中，我们研究了垫料弹虫 ( Sinella dubiosa ) 中 n-3 PUFA 的生物合成能力。我们在用啤酒酵母饲养的杜比奥萨（Sinella dubiosa）中检测到了 EPA ，该酵母仅产生饱和和单不饱和脂肪酸。此外，使用同位素标记的脂肪酸进行的代谢分析表明，油酸、亚麻酸和花生四烯酸在Sinella dubiosa中代谢为EPA 。鉴于跳虫是掠食性节肢动物的食物，其营养物质会转移到土壤食物网中的高级掠食性脊椎动物，我们建议跳虫作为土壤生态系统中的 EPA 来源。