Bees learn preferences for plant species that offer only pollen as a reward

The astonishing diversity of floral form in angiosperm plants is driven in large part by preferences of pollinators for various floral traits, including learned preferences. Remarkably, almost all of a vast literature on learning and memory in pollinators relates to nectar as a reward, even though bees and many flies, beetles, and butterflies must collect pollen. In this study, we asked if bees formed preferences for plant species from which pollen had been collected successfully. Using absolute conditioning, we gave pollen foraging bees experience with plant species that offered only pollen rewards. Naive bees generally showed modest preferences, whereas experienced bees adopted strong preferences for those species over alternative species not previously experienced. Learned preferences were retained for at least 24h, consistent with preferences learned with nectar rewards. These experience-mediated changes in preference raised the possibility that bees formed associations between part...被子植物（angiosperm plants）中令人惊叹的花部形态多样性，在很大程度上由传粉者（pollinators）对各类花部性状（包括后天习得的偏好）的选择所驱动。值得注意的是，尽管蜜蜂、多数蝇类、甲虫与蝴蝶均需采集花粉，但现有关于传粉者学习与记忆的海量研究中，几乎全部都将花蜜作为奖励对象展开探讨。本研究旨在探究蜜蜂是否会对其成功采集过花粉的植物物种产生偏好。本研究采用绝对条件反射（absolute conditioning）范式，让以花粉为觅食目标的蜜蜂接触仅提供花粉奖励的植物物种。未受训蜜蜂通常仅表现出微弱的偏好，而经训练的蜜蜂则会对该类植物物种产生显著强于未接触过的替代物种的偏好。习得的偏好至少可维持24小时，这与以花蜜为奖励的习得偏好表现一致。这类由觅食经历介导的偏好变化，提示蜜蜂可能会在[原文表述未完整]之间建立关联……