The research on animal colouration has always been of great interest for biologists but since the last decades it has grown exponentially thanks to multidisciplinary approaches. Animals have found several ways to deal with the camouflage/communication trade-off in colouration, leading to the evolution of alternative patterns of variation of colourations at different levels including signal partitioning and spatial resolution of colouration. In this paper we analyse the variability of dorsal and ventral colouration in males and females of Maltese wall lizards in three populations on Linosa. We collected high-resolution digital images of dorsal, ventral and throat colouration from 61 lizards (32 males and 29 females). We showed that the colouration differs among sexes and body regions within the same individual. Colourations are also variable among individuals within population, as well as among different populations across the Island. Finally, we detected a lizard’s colouration shifts with increasing body size. Those result supports the hypothesis that colouration in this species evolved under the competing pressures of natural and sexual selection to promote signals that are visible to conspecifics while being less perceptible to avian predators.

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中文翻译：

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利诺萨岛马耳他壁蜥（Podarcis filfolensis）在种群和个体水平上的颜色变化

生物学家对动物着色的研究一直很感兴趣，但自过去几十年以来，由于多学科方法，它呈指数级增长。动物已经找到了几种方法来处理着色的伪装/交流权衡，导致不同级别的着色变化的替代模式的演变，包括信号分区和着色的空间分辨率。在本文中，我们分析了 Linosa 上三个种群的马耳他壁蜥雄性和雌性背侧和腹侧颜色的变异性。我们收集了 61 只蜥蜴（32 只雄性和 29 只雌性）背部、腹侧和喉咙颜色的高分辨率数字图像。我们表明，同一个体的性别和身体区域的颜色不同。种群内的个体之间以及全岛不同种群之间的颜色也各不相同。最后，我们检测到蜥蜴的颜色随着体型的增加而变化。这些结果支持了这一假设，即该物种的颜色是在自然选择和性选择的竞争压力下进化的，以促进同种动物可见的信号，而鸟类捕食者则不易察觉。

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