The Floral Biology of Duchesnea (Rosaceae)



Abstract Pollinators and UV photos of flowers of Duchesnea chrysantha and D. indica are discussed. The petals of D. chrysantha reflect UV light strongly, while those of D. indica have a nectar guide appearing as a spot at the base of the petals that absorbs UV light. This is the same as in Potentilla which is closely related taxonomically. In Duchesnea, we consider the presence of a nectar guide to be a derived character. The petals of D. chrysantha and D. indica are distinguished by the presence or absence of nectar guides, but both species are pollinated mostly by the same kind of pollinators, which are commonly small polylectic insects. The main pollinators are four small bees (Andrena knuthi, A. minutula, Halictus aerarius, Lasioglossum sp.) and three syrphid flies (Paragus haemorrhous, Sphaerophoria macrogaster, S. philanthus). The total number of insect visitors in D. chrysantha was 60 species, while in D. indica there were 51. There was no significant difference in the visitors to the two Duchesnea species, therefore, the adaptive meaning of the presence of nectar guides was not determined in Duchesnea.