Pérez I de Lanuza Guillem, Ábalos Javier, Bartolomé Alicia, Font Enrique
CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, 4485-661 Vairão, Portugal
CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, 4485-661 Vairão, Portugal.
J Exp Biol. 2018 Mar 7;221(Pt 5):jeb169565. doi: 10.1242/jeb.169565.
Colour polymorphisms are thought to be maintained by complex evolutionary processes, some of which require that the colours of the alternative morphs function as chromatic signals to conspecifics. Unfortunately, a key aspect of this hypothesis has rarely been studied: whether the study species perceives its own colour variation as discrete rather than continuous. The European common wall lizard () presents a striking colour polymorphism: the ventral surface of adults of both sexes may be coloured orange, white, yellow or with a mosaic of scales combining two colours (orange-white, orange-yellow). Here, we used a discrimination learning paradigm to test whether is capable of discriminating colour stimuli designed to match the ventral colours of conspecifics. We trained 20 lizards to eat from colour-coded wells bored in wooden blocks. Blocks had four colour-coded wells (orange, white, yellow and an achromatic control), but only one contained food (mealworm larvae). After six trials, the lizards performed significantly better than expected by chance, showing a decrease in both the number of wells explored and the latency to finding the food. Using visual modelling techniques, we found that, based on their spectral properties and the lizards' cone sensitivities, the ventral colours of correspond to discrete rather than continuous colour categories, and that colour discriminability (i.e. distance in perceptual space) varies depending on the morphs compared, which may have implications for signal detection and discrimination. These results suggest that can discriminate hue differences matching their own ventral colour variation.
颜色多态性被认为是由复杂的进化过程维持的，其中一些过程要求替代形态的颜色作为对同种个体的色度信号起作用。不幸的是，这一假设的一个关键方面很少被研究：即研究物种是否将其自身的颜色变异视为离散的而非连续的。欧洲普通壁蜥（Podarcis muralis）呈现出显著的颜色多态性：成年两性的腹面可能是橙色、白色、黄色或带有两种颜色（橙白、橙黄）组合的鳞片镶嵌图案。在这里，我们使用辨别学习范式来测试普通壁蜥是否能够辨别旨在匹配同种个体腹面颜色的颜色刺激。我们训练了20只蜥蜴从木块上钻的颜色编码孔中取食。木块有四个颜色编码孔（橙色、白色、黄色和一个消色差对照），但只有一个孔中有食物（黄粉虫幼虫）。经过六次试验后，蜥蜴的表现明显优于随机预期，探索的孔数量和找到食物的潜伏期都有所减少。使用视觉建模技术，我们发现，基于它们的光谱特性和蜥蜴的视锥细胞敏感性，普通壁蜥的腹面颜色对应于离散而非连续的颜色类别，并且颜色可辨别性（即感知空间中的距离）根据所比较的形态而变化，这可能对信号检测和辨别有影响。这些结果表明普通壁蜥能够辨别与其自身腹面颜色变异相匹配的色调差异。
