Nocturnal bees feed on diurnal leftovers and pay the price of day–night lifestyle transition

Bees exemplify flights under bright sunlight. A few species across bee families have evolved nocturnality, displaying remarkable adaptations to overcome limitations of their daylight-suited apposition eyes. Phase inversion to nocturnality in a minority of bees that co-exist with diurnal bees provide a unique opportunity to study ecological benefits that mediate total temporal niche shifts. While floral traits and sensory modalities associated with the evolution of classical nocturnal pollination syndromes, e.g. by bats and moths, are well-studied, nocturnality in bees represent a poorly understood, recently invaded, extreme niche.To test the competitive release hypothesis, we examine how nocturnality shapes foraging by comparing pollen loads, nest pollen and flower visitation of sympatric nocturnal and diurnal carpenter bees. We predicted that nocturnal bees primarily use night-blooming flowers, show little/no resource overlap with diurnal species and competitive release favours night-t...

蜜蜂是日间强光环境下飞行行为的典型范例。蜂类多个科下的少数物种演化出夜行性，进化出了卓越的适应性特征以克服其适配日间光照的并列复眼（apposition eye）所带来的生理局限。与日间蜂类共存的少数夜行性蜂类，其活动时间从日间反转至夜间的现象，为研究介导完整时间生态位转变的生态效益提供了独特的研究契机。尽管以蝙蝠、蛾类为代表的经典夜行传粉综合征（pollination syndrome）演化相关的花部性状与感官模态已得到充分研究，但蜂类的夜行性仍属于一个认知匮乏、新近被占据的极端生态位。为验证竞争释放假说（competitive release hypothesis），本研究通过比较同域分布的夜行性与日间木蜂（carpenter bee）的花粉负载、巢内花粉储备及访花行为，探究夜行性如何塑造其觅食策略。我们预测，夜行性蜂类主要利用夜间开花的植物，与日间蜂类几乎不存在/不存在资源重叠，且竞争释放有利于夜间……