CONSISTENT INTERPLANT VARIATION IN NECTAR CHARACTERISTICS OF MIRABILIS-MULTIFLORA

The volume and sugar content of nectar produced by flowers can affect plant reproductive success by influencing pollinator foraging behavior. Because temporally varying environmental factors can affect nectar characters, the likelihood of pollinator-mediated selection for nectar characters may be reduced. To determine the constancy of interplant variation in floral nectar, I measured the volume and sugar concentration of nectar produced by plants in a population of Mirabilis multiflora within and between seasons. The means and relative ranking of nectar characters varied widely among plants. The means were remarkably constant within a season and across three successive flowering seasons. Variation among plants in sugar produced per flower was significantly correlated with the number of flowers produced (r = 0.29) and sugar concentration of nectar was significantly correlated with the date of peak flowering (r = -0.33). Ramets of clones had similar nectar volumes and total sugar produced, while genetically distinct near neighbors did not, suggesting a genetic component to nectar production. I conclude that plants of M. multiflora vary widely, and consistently through time, in their nectar characters and that this variation could affect pollinator behavior.