Pollination of the yellow water lily Nuphar subintegerrima (Nymphaeaceae) by the shore fly Notiphila (Notiphila) maritima (Diptera: Ephydridae)

Abstract

The genus Nuphar (yellow water lilies) comprises 13 aquatic perennial species distributed throughout the temperate Northern Hemisphere (Lippok et al. 2000). Ecologists have been intrigued by the pollination of Nuphar species. Schneider and Moore (1977) concluded that the chrysomelid beetle Donacia piscatrix is the most efficient pollinator of Nuphar lutea in North America. They also suggested that this pollination relationship might have involved through coevolution between the Nuphar and Donacia piscatrix. However, recent studies have reported more divergent relationships betweenNuphar species and other insect pollinators. Ervik et al. (1995) reported that Nuphar lutea is mainly pollinated by the honeybee Apis mellifera, bumblebees Bombus spp. and syrphid flies in southern Norway. Lippok and Renner (1997) also reported that N. lutea and Nuphar pumila are mainly pollinated by scatophagid flies and Ephydridae flies (shore fly) in Germany and Norway. Moreover, Lippok et al. (2000) reported that Nuphar ozarkana and Nuphar advena flowers were mainly visited by sweat bees in North America. Fieldwork in Europe and North America has shown that Nuphar species are also pollinated by shore flies (S. S. Renner, pers. comm., 2005). Thien et al. (2000) reported that extant basal angiosperms, such as Nymphaeaceae, are dominated by bisexual, protogynous and fragrant flowers and mainly pollinated by beetles and flies. However, there have been no studies examining the pollination systems of any Asian Nuphar species. The present study provides information on the flowering phenology and fruit set of a Nuphar species in western Japan and illustrates a possible pollination mutualism with shore flies.