Adipokinetic hormones (AKHs), the neurohormones synthesized in the insect corpora cardiaca are known to mobilize lipids and carbohydrates for energy‐consuming activities including reproduction. However, both inhibitory and stimulatory effects of AKHs on insect reproduction have been reported, and the underlying mechanisms remain elusive. Using the migratory locust, Locusta migratoria, as a model system, we report here that AKHs are expressed in response to rhythmic diel change, and AKH III expression increases markedly at photophase. Diurnal injection of AKH III but not AKH I or AKH II in adult females stimulates vitellogenesis and egg development. In contrast, AKH treatment at scotophase represses female reproduction. RNA interference‐mediated knockdown of AKH receptor (AKHR) results in significantly reduced vitellogenin (Vg) expression in the fat body at photophase along with reduced Vg deposition in the ovary. AKHR knockdown also leads to decreased expression of Brummer, triacylglycerol lipase and trehalose transporter, accompanied by suppressed mobilization of triacylglycerol and trehalose. We propose that in addition to stimulating Vg expression at photophase, AKH/AKHR signalling is likely to regulate ovarian uptake of Vg via triacylglycerol mobilization and trehalose homeostasis. This study provides new insights into the understanding of AKH/AKHR signalling in the regulation of insect reproduction.

中文翻译：

---

脂肪代谢激素的节律性变化每日调节蝗虫卵黄形成和卵的发育。

已知在心脏cardiac虫体内合成的脂肪动力学激素（AKHs）会动员脂质和碳水化合物进行能量消耗活动，包括生殖。然而，已经报道了AKHs对昆虫繁殖的抑制和刺激作用，并且其潜在机制仍然难以捉摸。使用迁移的蝗虫Locusta migratoria作为模型系统，我们在这里报告说，AKH s是对节律性diel变化的响应而表达的，而AKH III的表达在光相时显着增加。每天注射成年雌性的AKH III而不是AKH I或AKH II会刺激卵黄发生和卵子发育。相反，在近生阶段进行AKH处理会抑制雌性生殖。RNA干扰介导的敲除AKH受体（AKHR）导致光相中脂肪体中的卵黄蛋白原（Vg）表达显着降低，同时Vg在卵巢中的沉积降低。AKHR敲低还导致Brummer，三酰基甘油脂酶和海藻糖转运蛋白的表达降低，并伴有三酰基甘油和海藻糖的动员受到抑制。我们建议除了刺激Vg在光相表达中，AKH / AKHR信号可能通过三酰基甘油动员和海藻糖稳态来调节卵巢对Vg的吸收。这项研究为了解AKH / AKHR信号传导调控昆虫繁殖提供了新的见解。