Domesticated honeybees facilitate interspecific hybridization between two Taraxacum congeners

1. Interspecific hybridization is common in plants under natural conditions, but the ecological mechanisms underlying when and how it happens have not fully been understood.
2. Taraxacum calanthodium and T. lugubre are two herbaceous annals co-occurring in alpine meadows of the eastern Tibetan Plateau that share the same pollinators including domestic honeybees during their overlapping flowering times. Because honeybees tend to visit flowers less discriminatively when bee densities are high, we hypothesized that intense apiculture would facilitate hybridization between these two congeneric species.
3. We tested this hypothesis by examining the frequencies of the two parent species occurrence and the hybrid (based on morphological and genetic differences) along three transects radiating from well-established apiaries.
4. Experiments show that both Taraxacum calanthodium and T. lugubre produce seeds sexually and asexually, and that they can hybridize via pollen transfer. Bee visitation...

1. 种间杂交在自然条件下的植物中较为常见，但其发生的时机与背后的生态学机制尚未完全阐明。
2. 华丽蒲公英（Taraxacum calanthodium）与Taraxacum lugubre（简称T. lugubre）为两种伴生于青藏高原东部高山草甸的一年生草本植物，二者在花期重叠阶段共享包括家养蜜蜂在内的传粉者。鉴于蜜蜂种群密度较高时往往对访花缺乏选择性，我们提出假设：高强度养蜂业会促进这两个同属物种间的杂交。
3. 我们通过沿3条从成熟养蜂场向外延伸的样带，对两个亲本物种及杂交个体（基于形态与遗传差异进行区分）的出现频率开展调查，以此验证上述假设。
4. 实验表明，华丽蒲公英（Taraxacum calanthodium）与T. lugubre均可通过有性与无性两种方式产生种子，且二者可通过花粉传递实现杂交。蜜蜂访花……