Reproduction in Polemonium: Competition for Pollinators

Abstract

The flowering season of Polemonium foliosissimum Gray (Polemoniaceae) can be divided into two distinct periods. In the first, the bee:flower ratio is relatively high and large numbers of seeds per ovary are set. In addition, no correlation exists between the ollinator visitation rate to flowers and seed—set. In the second period the bee:flower ratio and seed—set are lower and a very strong correlation exists between pollinator service and seed—set. Pollinators are limiting resources during this portion of the season and those individual plants which can best attract pollinators have a strong selective advantage at this time. The evidence suggests that intraspecific exploitation competition for pollinator service might be occurring during this portion of the flowering season.