Flower colour polymorphism in Anemone coronaria correlates with the activity pattern and colour preferences of its visitors

Background and Aims Shifts in pollinator composition and associated colour preferences can support flower colour polymorphism (FCP) across environmental gradients and along flowering seasons. We explored the geographical and seasonal turnover of insect visitors in Anemone coronaria, a geophyte that flowers mainly in red, purple and white. In Israel, southern populations have red flowers whereas some northern populations are colour-polymorphic. Southern populations bloom later than northern ones, and red flowers appear later than non-red flowers. We predicted corresponding changes in colour preferences of A. coronaria’s pollinators, from non-red in northern sites and early in the season to red in southern sites and in late-season. Methods We created experimental arrays of red, purple, and white A. coronaria flowers in three field sites (northern, central, southern regions of the species’ distribution) and three time-points (early-, mid- and late-season) over two years. We recorded flower colour choices of insect visitors. Key Results Insect colour preferences varied among locations and time points. Bees and flies visited the flower arrays primarily during early-season in the northern and central sites, where bees preferred purple flowers. Beetles visited the flowers mostly during late season in the southern site and preferred red flowers there. Conclusions As predicted, A. coronaria’s purple flowers received more early-season visits in the north, and red flowers received more late-season visits in the south. These spatiotemporal trends are consistent with the species’ FCP pattern. A. coronaria’s broad pollinator fauna may enhance reproductive success across the plant's wide geographical distribution and long flowering season.