Intermittent food shortages are commonly encountered in the wild. To cope with the threat of starvation, insects initiate a suite of behavioral activities and physiological countermeasures. The cotton bollworm, Helicoverpa armigera, is a major agricultural pest worldwide, but how H. armigera modulates its metabolism under starvation remains ambiguous. In the present study, the respiratory rates (V̇O2; ml g-1 h-1) from the third-larval instar to the pupal stage were first determined. Our results highlighted a transient rise during the larval-larval molt and larval-pupal transition, followed by a sharp decline in the pupal stage and, finally, an upward trend before eclosion. When subjected to food deprivation, the starved larvae experienced a significant decline in the rates of O2 consumed and CO2 produced, as well as in respiratory quotient (RQ) values, indicative of severe metabolic depression during starvation and a shift of metabolic substrates with prolonged starvation. For metabolic substrate analysis, an apparent decline in triglyceride and glycogen contents was observed in the starved larvae, and the hemolymph trehalose content was significantly reduced throughout starvation. In addition, comparative transcriptome analysis showed that 48 h of larval starvation caused substantial transcriptional regulations in several energetically costly processes, wherein the marked up-regulations were detected in the pathways of glycolysis and fatty acid metabolism. Overall, our work makes a comprehensive study on the respiratory rate and energy metabolism in the starved H. armigera larvae, and provides a deep insight into the physiological adaptive strategies to alleviate nutritional stress.

中文翻译：

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饥饿对棉铃虫Helicoverpa armigera（Hübner）（鳞翅目：夜蛾科）的呼吸代谢和能量代谢的影响。

在野外经常遇到间歇性食物短缺。为了应对饥饿的威胁，昆虫发起了一系列行为活动和生理对策。棉铃虫棉铃虫（Helicoverpa armigera）是世界范围内的一种主要农业害虫，但棉铃虫在饥饿状态下如何调节其新陈代谢仍然不清楚。在本研究中，首先确定了从第三龄幼虫到the期的呼吸频率（V̇O2； ml g-1 h-1）。我们的研究结果强调了幼虫-幼虫蜕皮和幼虫-pal过渡期间的短暂上升，随后up期急剧下降，最后在脱落前呈上升趋势。遭受食物剥夺时，饥饿的幼虫的O2消耗速率和产生的CO2速率显着下降，以及呼吸商（RQ）值，表明饥饿期间严重的代谢抑制和饥饿时间延长的代谢底物的迁移。对于代谢底物分析，在饥饿的幼虫中甘油三酯和糖原含量明显下降，并且整个饥饿期间血淋巴海藻糖含量均显着降低。此外，比较转录组分析显示，幼虫饥饿48小时在几个耗费能量的过程中引起大量的转录调控，其中在糖酵解和脂肪酸代谢途径中检测到明显的上调。总体而言，我们的工作对饥饿的棉铃虫幼虫的呼吸频率和能量代谢进行了全面研究，