Female mosquitoes produce eggs in gonadotrophic cycles that are divided between a previtellogenic and vitellogenic phase. Previtellogenic females consume water and sugar sources like nectar while also being attracted to hosts for blood feeding. Consumption of a blood meal activates the vitellogenic phase, which produces mature eggs and suppresses host attraction. In this study, we tested the hypothesis that neuropeptide Y-like hormones differentially modulate host attraction behavior in the mosquito Aedes aegypti . A series of experiments collectively indicated that enteroendocrine cells (EECs) in the posterior midgut produce and release neuropeptide F (NPF) into the hemolymph during the previtellogenic phase which stimulates attraction to humans and biting behavior. Consumption of a blood meal, which primarily consists of protein by dry weight, down-regulated NPF in EECs until mature eggs developed, which was associated with a decline in hemolymph titer. NPF depletion depended on protein digestion but was not associated with EEC loss. Other experiments showed that neurons in the terminal ganglion extend axons to the posterior midgut and produce RYamide, which showed evidence of increased secretion into circulation after a blood meal. Injection of RYamide-1 and -2 into previtellogenic females suppressed host attraction, while coinjection of RYamides with or without short NPF-2 also inhibited the host attraction activity of NPF. Overall, our results identify NPF and RYamide as gut-associated hormones in A. aegypti that link host attraction behavior to shifts in diet during sequential gonadotrophic cycles.

中文翻译：

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神经肽 F 和 RYamide 之间的相互作用调节埃及伊蚊的宿主吸引力


雌性蚊子在促性腺激素周期中产生卵，该周期分为卵黄发生前阶段和卵黄发生阶段。卵黄发生前的雌性会消耗水和花蜜等糖源，同时也会被宿主吸引来吸血。食用血粉会激活卵黄形成阶段，产生成熟的卵子并抑制宿主的吸引力。在这项研究中，我们测试了这样的假设：神经肽 Y 样激素差异调节埃及伊蚊的宿主吸引行为。一系列实验共同表明，中肠后部的肠内分泌细胞 (EEC) 在卵黄发生前阶段产生神经肽 F (NPF) 并将其释放到血淋巴中，从而刺激对人类的吸引力和咬合行为。血粉主要由干重蛋白质组成，食用血粉会下调 EEC 中的 NPF，直至成熟卵发育，这与血淋巴滴度下降有关。 NPF 消耗取决于蛋白质消化，但与 EEC 损失无关。其他实验表明，终末神经节中的神经元将轴突延伸至后中肠并产生 RYamide，这表明吸血后循环中的分泌增加。将RYamide-1和-2注射到卵黄发生前的雌性中抑制了宿主吸引，而同时注射RYamides与或不与短NPF-2一起也抑制了NPF的宿主吸引活性。总体而言，我们的结果将 NPF 和 RYamide 确定为埃及伊蚊的肠道相关激素，将宿主吸引行为与连续促性腺激素周期期间的饮食变化联系起来。