title: Variation in pollen-donor composition among pollinators in an entomophilous tree species, Castanea crenata, revealed by single-pollen genotyping.
abstract: BACKGROUND
  In plants, reproductive success is largely determined by the composition of pollen (i.e., self-pollen and outcross-pollen from near and distant pollen-donors) transported as a result of pollinator foraging behavior (e.g., pollen carryover). However, little evidence is available on how and to what extent the pollen carryover affects the pollen-donor composition and on which insect taxa are effective outcross-pollen transporters under field conditions. In this study, we explored roles of foraging behavior of insect pollinators on pollen-donor composition and subsequent reproductive success in a woody plant.
  
  
  METHODS
  We performed paternity analyses based on microsatellite genotyping of individual pollen grains found on diurnal pollinators (i.e., bumblebee, small bee, fly, small beetle, and honeybee) visiting Castanea crenata trees.
  
  
  RESULTS
  The outcross-pollen rate was highest in bumblebees (66%), followed by small bees (35%), flies (31%), and small beetles (18%). The effective number of pollen donors, representing pollen carryover, was greater in bumblebees (9.71) than in flies (3.40), small bees (3.32), and small beetles (3.06). The high percentages of pollen from outside the plot on bumblebees (65.4%) and flies (71.2%) compared to small bees (35.3%) and small beetles (13.5%) demonstrated their longer pollen dispersal distances.
  
  
  CONCLUSIONS
  All of the diurnal insects carried outcross-pollen grains for long distances via pollen carryover. This fact suggests that a wide range of insect taxa are potential outcross-pollen transporters for the self-incompatible C. crenata.
authors: Graduate School of Agricultural Science, Tohoku University, Osaki, Miyagi, Japan; Institute of Wood Technology, Akita Prefectural University, Noshiro, Akita, Japan.
authors: Yoichi
authors: Y
authors: Hasegawa
authors: Graduate School of Agricultural Science, Tohoku University, Osaki, Miyagi, Japan.
authors: Yoshihisa
authors: Y
authors: Suyama
authors: Graduate School of Agricultural Science, Tohoku University, Osaki, Miyagi, Japan.
authors: Kenji
authors: K
authors: Seiwa
mesh_terms: D000818:Animals; D029962:Fagaceae / Q000235:genetics* / Q000502:physiology; D014644:Genetic Variation; D018745:Genome, Plant; D005838:Genotype; D007313:Insecta / Q000145:classification / Q000502:physiology; D018895:Microsatellite Repeats; D011058:Pollen / Q000235:genetics*; D054817:Pollination