Hardenbicker Marie-Christin, Schubert Joseph, Tedore Cynthia
Institute for Animal Cell and Systems Biology University of Hamburg Hamburg Germany.
School of Life and Environmental Sciences University of Sydney Sydney New South Wales Australia.
Ecol Evol. 2025 May 23;15(5):e71363. doi: 10.1002/ece3.71363. eCollection 2025 May.
The form of arbitrary sexual signals may be driven by the need to be detectable against the background or, alternatively, by selection for efficient processing by the nervous system. This latter alternative is a prediction of the sensory drive hypothesis extended to include efficient coding as a driver of the form of sexual signals. This hypothesis posits that animal visual systems are adapted to process the visual statistics of natural scenes, and that easily processed stimuli induce a sensation of pleasure in the viewer. In support of this, natural scene statistics have been found to be preferred not only by humans, but by the peacock spider . Here we test if male peacock spiders of the highly sexually dimorphic genus generally (a) evolve colour patterns with image statistics that contrast with the natural background or (b) exploit a potential processing bias by evolving colour patterns with visual statistics similar to those of natural scenes. We analyse and compare multispectral images of male and female spiders of 21 species and of natural scenes similar to the spiders' habitat. We find that the image statistics of male patterns diverge from those of natural scenes, whereas the statistics of female patterns do not. Our results support the idea that colour patterns evolve contrasting image statistics to increase conspicuousness and matching image statistics to be camouflaged. Any processing bias for natural scene image statistics in thus appears to play little role in the evolution of their sexual signals.
任意性信号的形式可能是由在背景中可被检测到的需求所驱动，或者，是由神经系统进行高效处理的选择所驱动。后一种情况是对感官驱动假说的一种预测，该假说扩展到将高效编码作为性信号形式的驱动因素。这一假说假定动物视觉系统适应于处理自然场景的视觉统计信息，并且易于处理的刺激会在观察者身上引发愉悦感。支持这一点的是，不仅人类，孔雀蜘蛛也表现出对自然场景统计信息的偏好。在这里，我们测试高度两性异形的孔雀蜘蛛属的雄性蜘蛛是否通常（a）进化出与自然背景形成对比的图像统计特征的颜色图案，或者（b）通过进化出与自然场景视觉统计特征相似的颜色图案来利用潜在的处理偏差。我们分析并比较了21种蜘蛛的雄性和雌性蜘蛛以及与蜘蛛栖息地相似的自然场景的多光谱图像。我们发现雄性图案的图像统计特征与自然场景不同，而雌性图案的统计特征则不然。我们的结果支持这样一种观点，即颜色图案通过进化出对比的图像统计特征来增加显眼性，并通过匹配图像统计特征来实现伪装。因此，对于自然场景图像统计信息的任何处理偏差似乎在它们性信号的进化中作用不大。
