Declining floral color diversity shifts bee color preferences in fragmented habitats

Habitat fragmentation reduces floral color diversity in plant communities, shifting in color preferences of bee pollinators as shown by altered visitation frequency. We conducted a two-year survey of plant-bee interactions on 41 islands and the adjacent mainland habitats in a reservoir island system of eastern China. Reflectance spectra of the flower samples were measured using a portable spectrometer. Results showed that floral color composition was predominantly blue-green and blue, and a reduction in island area significantly decreased floral color diversity. Visitation frequencies to blue-green, ultraviolet-blue, and ultraviolet-green floral colors declined significantly with decreasing island area. Changes in floral color diversity altered bees’ color preferences, significantly impacting total floral visitation frequency. Bees’ color preference for blue-green flowers increased with island area, and floral resources showed no significant effect on visitation frequencies., , # Declining floral color diversity shifts bee color preferences in fragmented habitats

Dataset DOI: [10.5061/dryad.612jm64gq](10.5061/dryad.612jm64gq)

## Description of the data and file structure

We selected 41 islands (seven large islands (>20 ha) and 34 small islands) and 16 mainland sampling sites for field surveys in Thousand Island Lake. We conducted biweekly surveys covering all islands from March 22 to July 15, 2023, and from March 26 to July 23, 2024. For each year, we had seven replicated surveys. Each survey was carried out on days without rain or strong winds during two time slots: 8:30-12:00 and 13:00-17:00. At each site, we established fixed transects (100-m long × 4-m wide) in edge habitats with high flowering herb richness and another in interior habitats extending inward from the edge. Edge transects were surveyed for 15 minutes, and interior transects for 10 minutes per visit. We recorded bee visits, defined as contact with anthers or stigmas on flowers of herbs, sh...,