Meng Linqin, Wei Dandan, Feng Yuanze, Zang Jiancheng, Cheng Weining, Jing Xiangfeng
Key Laboratory of Plant Protection Resources and Pest Management of Ministry of Education, Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau of Ministry of Agriculture and Rural Affairs, College of Plant Protection, Northwest A&F University, Yangling 712100 Shaanxi, China.
Plant Science College, Xizang Agriculture & Animal Husbandry University, Linzhi 860000 Xizang, China.
J Insect Physiol. 2025 Jul;164:104826. doi: 10.1016/j.jinsphys.2025.104826. Epub 2025 Jun 7.
Plant sterols constitute the sole source of sterol nutrition for insect herbivores, yet the sterol content of plants is complex and variable, and insect sterol nutrient regulation remains to be elucidated. In this study, we investigated cholesterol regulation inSpodoptera frugiperda using a geometric framework for nutrition. In the choice experiment, we provided larvae with eight food pairings. The insects did not adjust their feeding on the pair of complementary diets to achieve a specific cholesterol intake target. In the no-choice experiment, seven foods with different cholesterol concentrations were administered to explore sterol regulation. The larvae did not show a tendency to reduce or increase their intake of non-cholesterol nutrients to reach a certain cholesterol intake. We then measured the relative expression of the NPC1b gene in the intestine and the cholesterol content of the feces. As the cholesterol content in the food increased, NPC1b gene expression gradually decreased and the larvae excreted more cholesterol in the feces. Meanwhile, the cholesterol content in the larvae remains largely consistent, indicating that the larvae has a strong control on the body sterol content. Altogether, our results suggest that the larvae regulate cholesterol homeostasis by balancing cholesterol uptake and excretion, and cholesterol level can be kept within a physiologically appropriate range.
植物甾醇是昆虫食草动物甾醇营养的唯一来源，但植物的甾醇含量复杂且多变，昆虫甾醇营养调节仍有待阐明。在本研究中，我们使用营养几何框架研究了草地贪夜蛾中胆固醇的调节。在选择实验中，我们为幼虫提供了八种食物组合。昆虫没有通过调整对互补饮食组合的摄食来实现特定的胆固醇摄入目标。在无选择实验中，给予七种胆固醇浓度不同的食物以探索甾醇调节。幼虫没有表现出减少或增加非胆固醇营养素摄入量以达到一定胆固醇摄入量的趋势。然后，我们测量了肠道中NPC1b基因的相对表达和粪便中的胆固醇含量。随着食物中胆固醇含量的增加，NPC1b基因表达逐渐降低，幼虫粪便中排出的胆固醇增多。同时，幼虫体内的胆固醇含量基本保持一致，表明幼虫对体内甾醇含量有很强的调控能力。总之，我们的结果表明，幼虫通过平衡胆固醇的摄取和排泄来调节胆固醇稳态，并且胆固醇水平可以保持在生理适当范围内。
