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...