Insect neuropeptides regulate various physiological processes, such as reproduction, feeding, growth and development, and have been considered as viable targets in the development of alternative strategies for pest control. Amongst these neuropeptides is myosuppressin (MS), a very conserved neuropeptide that has been reported to regulate cardiac and skeletal muscle contractility, feeding and pupal diapause in insects. In this study, we investigated the involvement of MS in fecundity in a notorious defoliator of potato and other solanaceous plants, the Colorado potato beetle (CPB), Leptinotarsa decemlineata. We identified an MS-precursor-encoding transcript in the L. decemlineata transcriptomic database and then evaluated its transcript levels in various CPB tissues. MS transcript levels were found to be highest in the central nervous system, gut and muscle of CPB males and females. To investigate the role of MS in fecundity, MS was silenced in adult CPBs through RNA interference (RNAi). This resulted in a significant reduction in oviposition (over 80%) and oocyte size (69%) in the treated beetles compared to the controls. Also, the reduction in oviposition in treated females was confirmed to be dependent on MS knockdown and independent of male fertilization. Furthermore, MS-knockdown in females resulted in decreased levels of ecdysteroid hormone titers and the transcript levels of its receptor. Interestingly, the injection of 20-hydroxyecdysone into females following MS knockdown could rescue ovary development. Altogether, this study highlights the important role played by MS in regulating fecundity in CPB.

中文翻译：

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肌抑制素影响科罗拉多马铃薯甲虫 Leptinotarsa decemlineata 的繁殖力

昆虫神经肽调节各种生理过程，如繁殖、摄食、生长和发育，并已被认为是开发害虫控制替代策略的可行目标。在这些神经肽中，肌抑制素 (MS) 是一种非常保守的神经肽，据报道可调节昆虫的心脏和骨骼肌收缩力、摄食和蛹滞育。在这项研究中，我们调查了 MS 与臭名昭著的马铃薯和其他茄科植物——科罗拉多马铃薯甲虫 (CPB)、Leptinotarsa decemlineata 的落叶者的繁殖力有关 。我们在L. decemlineata 中鉴定了 MS 前体编码转录本转录组数据库，然后评估其在各种 CPB 组织中的转录水平。发现 CPB 男性和女性的中枢神经系统、肠道和肌肉中的 MS 转录水平最高。为了研究 MS 在繁殖力中的作用，通过 RNA 干扰 (RNAi) 在成人 CPB 中沉默 MS。与对照组相比，这导致处理过的甲虫的产卵量（超过 80%）和卵母细胞大小（69%）显着减少。此外，经处理的雌性产卵量的减少被证实依赖于 MS 击倒而不依赖于雄性受精。此外，在雌性中敲除 MS 导致蜕皮类固醇激素滴度水平及其受体的转录水平降低。有趣的是，在 MS 敲低后向雌性注射 20-羟基蜕皮激素可以挽救卵巢发育。