Department of Forest Nature Conservation, Georg-August-University of Göttingen, Göttingen, Germany.
Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria.
Evolution. 2024 May 29;78(6):1174-1182. doi: 10.1093/evolut/qpae052.
Although diurnality is widespread across Lepidoptera and has evolved many times independently, its causes and ecological implications are yet poorly understood. The "Salient Aroma Hypothesis" (SAH) postulates that diurnal insect herbivores are overall more specialized in dietary breadth than species active at night. It is furthermore assumed that diurnality evolved more frequently in species that live in cooler environments. Using European geometrid moths as a model group, we tested whether diurnal activity in adults is associated with an increased larval dietary breadth as predicted by the SAH. We further investigated whether species that exclusively occur in colder regions or whose flight period is restricted to cool seasons are more likely to exhibit a diurnal flight activity. Contrary to expectation, we found no consistent differences in larval dietary breadth between diurnal and nocturnal species, and thus no support for the SAH. Diurnal activity occurred more frequently in species restricted to cold regions but not in species restricted to cool seasons. We conclude that diurnality could serve as an advantageous adaptation in cold environments, depending on further factors such as resource availability or predation pressure, but has no immediate consequences for larval dietary breadth.
虽然昼行性在鳞翅目昆虫中广泛存在，并已多次独立进化，但它的成因和生态意义仍知之甚少。“显著香气假说”（SAH）假定，与夜间活动的物种相比，昼行性昆虫食草动物在饮食广度上总体更为专业化。此外，人们还假设昼行性在生活在较冷环境中的物种中更为频繁地进化。我们使用欧洲尺蛾作为模型组，检验了成虫的昼行性活动是否如 SAH 所预测的那样与增加幼虫的饮食广度有关。我们进一步研究了那些仅在较冷地区出现或飞行期仅限于凉爽季节的物种，是否更有可能表现出昼行性飞行活动。出乎意料的是，我们没有发现昼行性和夜行性物种之间幼虫饮食广度有一致的差异，因此无法支持 SAH。昼行性活动在仅限于寒冷地区的物种中更为常见，但在仅限于凉爽季节的物种中则不然。我们得出结论，昼行性可能是在寒冷环境中一种有利的适应，但这取决于进一步的因素，如资源可用性或捕食压力，而不会对幼虫的饮食广度产生直接影响。
