Supplementary Data from Concurrence in the ability for lipid synthesis between life stages in insects

The ability to synthesize lipids is critical for an organism's fitness; hence, metabolic pathways, underlying lipid synthesis, tend to be highly conserved. Surprisingly, the majority of parasitoids deviate from this general metabolic model by lacking the ability to convert sugars and other carbohydrates into lipids. These insects spend the first part of their life feeding and developing in or on an arthropod host, during which they can carry over a substantial amount of lipid reserves. While many parasitoid species have been tested for lipogenic ability at the adult life stage, it has remained unclear whether parasitoid larvae can synthesize lipids. Here we investigate whether or not several insects can synthesize lipids during the larval stage using three ectoparasitic wasps (developing on the outside of the host) and the vinegar fly Drosophila melanogaster that differ in lipogenic ability in the adult life stage. Using feeding experiments and stable isotope tracing with gas chromatography/mass spectrometry, we first confirm lipogenic abilities in the adult life stage. Using topical application of stable isotopes in developing larvae, we then provide clear evidence of concurrence in lipogenic ability between larval and adult life stages in all species tested.

脂质合成能力对于生物的适应性至关重要；因此，涉及脂质合成的代谢途径往往高度保守。令人惊讶的是，大多数寄生性昆虫偏离了这一普遍的代谢模式，它们缺乏将糖和其他碳水化合物转化为脂质的能力。这些昆虫在其生命周期的初期阶段，在或宿主昆虫体内或体外摄取食物并进行发育，在此期间，它们能够累积大量的脂质储备。尽管许多寄生性昆虫在成年生活阶段已测试其脂生成能力，但寄生性幼虫是否能够合成脂质仍然不甚明了。在本研究中，我们探讨了使用三种外寄生蜂（在宿主体外发育）和具有不同成年生活阶段脂生成能力的果蝇 Drosophila melanogaster，是否能够在幼虫阶段合成脂质。通过喂养实验和气相色谱/质谱法的稳定同位素追踪，我们首先在成年生活阶段确认了脂生成能力。然后，通过在发育幼虫上局部应用稳定同位素，我们为所有测试物种在幼虫和成年生活阶段脂生成能力的共存提供了明确证据。