title: Variation in highbush blueberry floral volatile profiles as a function of pollination status, cultivar, time of day and flower part: implications for flower visitation by bees.
abstract: OBJECTIVE
  Studies of the effects of pollination on floral scent and bee visitation remain rare, particularly in agricultural crops. To fill this gap, the hypothesis that bee visitation to flowers decreases after pollination through reduced floral volatile emissions in highbush blueberries, Vaccinium corymbosum, was tested. Other sources of variation in floral emissions and the role of floral volatiles in bee attraction were also examined.
  
  
  METHODS
  Pollinator visitation to blueberry flowers was manipulated by bagging all flowers within a bush (pollinator excluded) or leaving them unbagged (open pollinated), and then the effect on floral volatile emissions and future bee visitation were measured. Floral volatiles were also measured from different blueberry cultivars, times of the day and flower parts, and a study was conducted to test the attraction of bees to floral volatiles.
  
  
  RESULTS
  Open-pollinated blueberry flowers had 32 % lower volatile emissions than pollinator-excluded flowers. In particular, cinnamyl alcohol, a major component of the floral blend that is emitted exclusively from petals, was emitted in lower quantities from open-pollinated flowers. Although, no differences in cinnamyl alcohol emissions were detected among three blueberry cultivars or at different times of day, some components of the blueberry floral blend were emitted in higher amounts from certain cultivars and at mid-day. Field observations showed that more bees visited bushes with pollinator-excluded flowers. Also, more honey bees were caught in traps baited with a synthetic blueberry floral blend than in unbaited traps.
  
  
  CONCLUSIONS
  Greater volatile emissions may help guide bees to unpollinated flowers, and thus increase plant fitness and bee energetic return when foraging in blueberries. Furthermore, the variation in volatile emissions from blueberry flowers depending on pollination status, plant cultivar and time of day suggests an adaptive role of floral signals in increasing pollination of flowers.
authors.affiliation: Department of Entomology, P.E. Marucci Center for Blueberry & Cranberry Research & Extension, Rutgers University, Chatsworth, NJ 08019, USA. crodriguez@aesop.rutgers.edu
authors.forename: Cesar
authors.initials: C
authors.lastname: Rodriguez-Saona
authors.forename: Leonardo
authors.initials: L
authors.lastname: Parra
authors.forename: Andrés
authors.initials: A
authors.lastname: Quiroz
authors.forename: Rufus
authors.initials: R
authors.lastname: Isaacs
mesh_terms: D000818:Animals; D001516:Bees / Q000502:physiology*; D001522:Behavior, Animal / Q000502:physiology; D029798:Blueberry Plants / Q000033:anatomy & histology / Q000737:chemistry* / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology; D035264:Flowers / Q000033:anatomy & histology / Q000737:chemistry / Q000502:physiology*; D009812:Odorants; D057048:Plant Nectar / Q000096:biosynthesis; D054817:Pollination / Q000502:physiology*; D025341:Principal Component Analysis; D020005:Propanols / Q000032:analysis / Q000378:metabolism; D055549:Volatile Organic Compounds / Q000032:analysis / Q000378:metabolism*
chemical_list: D057048:Plant Nectar; D020005:Propanols; D055549:Volatile Organic Compounds; C020722:cinnamyl alcohol