Adaptive coloration among animals is one of the most recognizable outcomes of natural selection. Here, we investigate evolutionary drivers of white coloration in velvet ants (Hymenoptera: Mutillidae), which has previously been considered camouflage with the fruit of creosote bush (Larrea tridentata). Our analyses indicate instead that velvet ants evolved white coloration millions of years before creosote bush was widespread in North America's hot deserts. Furthermore, velvet ants and the creosote fruit exhibit different spectral reflectance patterns, which appear distinct to potential insectivorous predators. While the white coloration in velvet ants likely did not evolve as camouflage, we find that white-coloured species remain cooler than their red/orange relatives, and therefore we infer the white coloration likely evolved in response to Neogene desertification. This study shows the importance of cross-disciplinary investigation and of testing multiple hypotheses when investigating evolutionary drivers of adaptive coloration.

动物之间的自适应着色是自然选择最可识别的结果之一。在这里，我们研究了天鹅绒蚂蚁（膜翅目：Mutillidae）中白色着色的进化驱动力，该天鹅绒蚂蚁以前被认为是杂种灌木丛（Larrea tridentata）的果实。）。相反，我们的分析表明，天鹅绒蚂蚁在杂色灌木丛在北美炎热的沙漠中广泛分布之前已经发展了数百万年。此外，天鹅绒蚂蚁和杂酚果表现出不同的光谱反射模式，这对于潜在的食虫性捕食者似乎是不同的。尽管天鹅绒蚂蚁的白色可能不会伪装，但我们发现白色物种的颜色仍然比其红色/橙色亲戚凉爽，因此我们推断出可能是由于新近代荒漠化而演变的白色。这项研究表明，在研究适应性着色的进化驱动因素时，进行跨学科研究和检验多种假设的重要性。