Declining floral color diversity alters bee color preferences in fragmented habitats

Habitat fragmentation reduces floral color diversity in plant communities, thus resulting in a shift in bee pollinator color preferences, as shown by altered visitation frequency. We conducted a two-year survey of plant-bee interactions on 41 islands and adjacent mainland habitats in a reservoir island system of eastern China. Results showed that bee-blue-green and bee-blue dominated the floral color composition and that a reduction in island area significantly reduced floral color diversity. Visitation frequencies to bee-blue-green, bee-ultraviolet-blue, and bee-ultraviolet-green flowers declined significantly as island area decreased. These changes in floral color diversity altered the color preferences of bees, as shown by the significantly impacted total floral visitation frequencies. The preference for bee-blue-green flowers increased as island area increased, while floral resources showed no significant effect on visitation frequencies. In sum, these results improve our understanding of how pollinators adapt their behavior in fragmented habitats and provide important insights supporting the conservation of floral color diversity as well as the plant species associated with the colors that correspond to a high visitation frequency.