Pressing flowers between pages…
The importance of pollen theft to reproductive success in Polemonium foliosissimum. Over 75% of the flowering plants in temperate regions are pollinated by insects, and the evolution of floral traits has most often been attributed to attracting pollinators. Plants reward their mutualist pollinators primarily with nectar and pollen. Yet, not all insects that utilize nectar and pollen for food are pollinators. Here, I wish to examine how pollen thieves ? small flies in the family Muscidae ? affect reproductive success in the sub-alpine plant, Polemonium foliosissimum (commonly called ?sticky polemonium?). When watching these flies, one can see that they often completely strip the anthers of pollen and they don't pollinate the plant. In addition to robbing the plant of pollen, they may render plants functionally female (i.e., removing much of their male gametes) and alter sex-ratios for a sticky polemonium which has an unusual mating system whereby some plants are typical hermaphrodites and others don't produce pollen. Thus, these pollen thieves may have important consequences in enhancing pollen limitation for both females and hermaphrodites, altering sex ratios and, ultimately, affecting the ecology and evolution these plants as well as others.