Red bowel-shaped flowers: Convergence for beetle pollination in the Mediterranean region

Anemone coronaria, Papaver rhoeas, Ranunculus asiaticus, and Tulipa agenensis are pollinated primarily by scarabaeid beetles (Amphicoma, Glaphyridae) and secondarily by bees (Lasioglossum marginatum Br., Halictidae, and Synhalonia plumigera Kohl, Anthophoridae). The four plant species have large bowl-shaped flowers which are orange-red in color with a black center, radial symmetry, weak scent (to humans), and filamentous stamens. It is suggested that there is a convergent evolution of red bowl-shaped flowers in the East Mediterranean region, concordant with a center of diversity in the genus Amphicoma. The floral phenology of these “Poppy guild” species correlated positively with the amount of edible pollen produced by each of them and with the visiting frequencies of their pollinators. Field experiments showed that Amphicoma beetles also preferred red, odorless flower models over odorless models of different colors, and models with a dark center over plain red ones. This evidence extends the classic concepts of beetle pollination, suggesting a “shift” from scent to color as a primary attractant and the domination of orange-red (typical “bird-flower” colors) as the visual cue.