Publication Date


Document Type


Journal Article Version

Version of Record


TBA (In Press)


TBA (In Press)


Premise of the study

Reproductive fitness in plants is often determined by the quantity and quality of pollen transferred by pollinators. However, many fitness studies measure only female fitness, or rely on proxies for male fitness. Here we assess how five bee taxa affect male fitness in a prairie plant by quantifying pollen removal, visitation, and siring success using paternity assignments and a unique experimental approach.


In Echinacea angustifolia, we measured per-visit pollen removal for each pollinator taxa and estimated the number of pollen grains needed for successful ovule fertilization. Additionally, we directly measured pollinator influence on siring by allowing only one bee taxon to visit each pollen donor plant, while open-pollinated plants acted as unrestricted pollen recipients. We genotyped the resulting offspring, assigned paternity, and used aster statistical models to quantify siring success.

Key results

Siring success of pollen donor plants differed among five pollinator taxa. Non-grooming male bees were associated with increased siring success. Bees from all taxa removed most of the flowering head’s pollen in one visit. However, coneflower-specialist bee Andrena helianthiformis removed the most pollen per visit. Finally, female fitness and proxy measures of male fitness, such as pollinator visitation and pollen removal, did not align with our direct quantifications of male fitness.


Our results illustrate the need for more studies to directly quantify male fitness and we caution against using male fitness proxy measures. Additionally, we discuss how conservation efforts focused on preserving a diverse pollinator community can benefit plants in fragmented landscapes.


plant-pollinator interactions, male fitness, Asteraceae, Echinacea angustifolia, pollen removal, native bees, pollen movement, tallgrass prairie, plant reproduction, siring success

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