Endoparasitoid wasps inject venom along with their eggs to adjust the physiological and nutritional environment inside their hosts to benefit the development of their offspring. In particular, wasp venoms are known to modify host lipid metabolism, lipid storage in the fat body, and release of lipids into the hemolymph, but how venoms accomplish these functions remains unclear. Here, we use an UPLC-MS-based lipidomics approach to analyze the identities and concentrations of lipids in both fat body and hemolymph of host cabbage butterfly (Pieris rapae) infected by the pupal endoparasitoid Pteromalus puparum. During infection, host fat body levels of highly unsaturated, soluble triacylglycerides (TAGs) increased while less unsaturated, less soluble forms decreased. Furthermore, in infected host hemolymph, overall levels of TAG and phospholipids (the major component of cell membranes) increased, suggesting that fat body cells are destroyed and their contents are dispersed. Altogether, these data suggest that wasp venom induces host fat body TAGs to be transformed into lower melting point (more liquid) forms and released into the host hemolymph following infection, allowing simple absorption and nutritional acquisition by wasp larvae. Finally, cholesteryl esters (CEs, a dietary lipid derived from cholesterol) increased in host hemolymph following infection with no concomitant decrease in host cholesterol, implying that the wasp may provide this necessary food resource to its offspring via its venom. This study provides novel insight into how parasitoid infection alters lipid metabolism in insect hosts, and begins to uncover the wasp venom proteins responsible for host physiological changes and offspring development.

内寄生蜂将毒液与卵一起注射，以调整宿主体内的生理和营养环境，从而有利于后代的发育。特别是，已知黄蜂毒液可以改变宿主脂质代谢、脂肪体中的脂质储存以及将脂质释放到血淋巴中，但毒液如何完成这些功能仍不清楚。在这里，我们使用基于 UPLC-MS 的脂质组学方法来分析被蛹内寄生蜂 Pteromalus puparum感染的宿主菜粉蝶 ( Pieris rapae ) 脂肪体和血淋巴中脂质的特性和浓度. 在感染期间，宿主脂肪体的高度不饱和、可溶性甘油三酯 (TAG) 水平增加，而不饱和度较低、可溶性较低的形式则减少。此外，在受感染的宿主血淋巴中，TAG 和磷脂（细胞膜的主要成分）的总体水平增加，表明脂肪体细胞被破坏并且其内容物分散。总之，这些数据表明，黄蜂毒液诱导宿主脂肪体 TAG 转化为较低熔点（更多液体）的形式，并在感染后释放到宿主血淋巴中，从而允许黄蜂幼虫简单地吸收和获取营养。最后，感染后宿主血淋巴中的胆固醇酯（CEs，一种源自胆固醇的膳食脂质）增加，而宿主胆固醇没有随之降低，通过它的毒液。这项研究为寄生虫感染如何改变昆虫宿主的脂质代谢提供了新的见解，并开始揭示负责宿主生理变化和后代发育的黄蜂毒蛋白。