The occurrence of different color patterns in a population of a species can depend on genetic variations or plasticity to environmental conditions. Body color variation is under selection because it is involved in several ecological processes such as camouflage for prey-predator interactions or resistance to environmental variations. Among insects, aphids are known to produce different body-color morphs depending on their biotic and abiotic environments and their bacterial endosymbionts. The English-grain aphid (EGA) Sitobion avenae produces both red and green morphs in cereal fields. Using both field studies on the Canadian prairies (Saskatchewan) and laboratory experiments, we aimed to study the mechanisms that trigger plasticity in body coloration to better understand the ecological role of body coloration and color-change evolved by animals, including aphids. We first analyzed green and red morph EGA distribution on wheat ears in different fields and showed that red aphids were mostly located at the top of the ear and green aphids at the bottom. Then, using DNA sequencing, we showed that red and green morphs did not strongly differ in their bacterial endosymbiont composition and abundances. Finally, using a climate-chamber setup in the laboratory, we highlighted that EGA body-coloration is under light-intensity control and that it is possible to turn aphids from red back to green within a few days, and from green back to red within a couple of weeks (low-to-high and high-to-low light intensities, respectively). Light-intensity-controlled color-change likely results in adaptive plasticity in response to shifts in environmental conditions that can occur over the lifespan of an aphid, and is fully reversible, even at the adult stage.

中文翻译：

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在实验室和田间条件下英国谷蚜对光的体色可塑性

一个物种种群中不同颜色图案的出现可能取决于遗传变异或对环境条件的可塑性。体色变化正在被选择，因为它涉及几个生态过程，例如伪装猎物 - 捕食者相互作用或抵抗环境变化。在昆虫中，已知蚜虫会根据其生物和非生物环境及其细菌内共生体产生不同的体色变体。英国谷物蚜虫 (EGA) Sitobion avenae 在谷物田中产生红色和绿色变体。通过对加拿大大草原（萨斯喀彻温省）的实地研究和实验室实验，我们旨在研究触发身体颜色可塑性的机制，以更好地了解动物进化的身体颜色和颜色变化的生态作用，包括蚜虫。我们首先分析了不同田间小麦穗的绿色和红色形态 EGA 分布，发现红色蚜虫主要位于穗顶部，绿色蚜虫位于底部。然后，使用 DNA 测序，我们发现红色和绿色变体的细菌内共生体组成和丰度没有很大差异。最后，使用实验室中的气候室设置，我们强调了 EGA 体色受光强度控制，并且有可能在几天内将蚜虫从红色变回绿色，并在几天内从绿色变回红色几周（分别为低到高和高到低的光强度）。光强度控制的颜色变化可能会导致适应性可塑性，以响应蚜虫整个生命周期中可能发生的环境条件变化，