Dose‐response relationships between pollination and fruiting refine pollinator comparisons for cranberry (Vaccinium macrocarpon [Ericaceae])

Abstract

Comparisons of pollinator efficacy using pollen received on stigmas can be refined by incorporating experimental dose-response relationships for pollen deposition and fruiting responses. A range of discrete pollen doses applied to cranberry stigmas resulted in decelerating curvilinear responses for fruiting, berry size, and seed set. Minimum thresholds and maximum asymptotes bounded reproductive responses to incremental stigmatic pollen loads. Four bee species were compared for their pollination efficacies on commercial cranberries, using counts of pollen received by stigmas during single bee visits to previously virgin flowers. Differences between these bee species were found to be exaggerated when raw pollen counts were used for comparison because foragers of some species often delivered pollen in excess of that needed to maximize fruit and seed production. Sixfold differences between species in mean pollen deposition translated into 1.5-2-fold differences in predicted cranberry fruit set and size. Implications for pollen tube competition and agricultural production are discussed.

Importance of pollinators in changing landscapes for world crops

“…Studies that compare fruit or seed set of flowers in treatments with and without access by wild-pollinating species or with additional hand-pollination provide important data to identify key pollinating species (Canto-Aguilar & Parra-Tabla 2000; Javorek et al 2002;Cane & Schiffhauer 2003;Klein et al 2003a,b;Greenleaf & Kremen 2006, in press;Blanche et al in press), but few such studies are yet available. In spite of this information shortage, many reviews mention the neglected potential of wild bee species for crop pollination (O'Toole 1993;Corbet 1996;Williams 1996;Westerkamp & Gottsberger 2000;Goulson 2003).…”

Per-visit pollinator performance and regional importance of wild Bombus and Andrena (Melandrena) compared to the managed honey bee in New York apple orchards

“…Based on pollen transfer alone, wild bees were more effective per-visit; however, translating pollinator effectiveness to efficiency revealed that pollinator performance was similar among our focal bees at the level of a single visit (Cane and Schiffhauer 2003). Previous work identifying Melandrena and Bombus as alternative pollinators of apple relied on pollen deposition and other proxies of pollinator efficiency: higher pollen transfer by Bombus compared with Apis (Thomson and Goodell 2001); high body counts and proportions of apple pollen found on Bombus and andrenids, notably Melandrena (Boyle and Table II.…”

“…Aside from comparing foraging behaviors and pollen carried by pollinators (as described above), pollination ecologists rely heavily on pollen deposition as a proxy for per-visit performance of pollinators in pollination studies, including those focused on crops, due to the relative ease of collecting such data (e.g., pumpkin, Hoehn et al 2008;blueberry, Javorek et al 2002;watermelon, Kremen et al 2002;Pak-choi, Rader et al 2009;coffee, Ricketts 2004;and apple, Thomson and Goodell 2001). Unfortunately, pollen transfer does not translate completely to reproductive success (i.e., fruit set or seed set), arguably a more accurate measure of a pollinator's performance (Cane and Schiffhauer 2003). First, the relationship between pollen deposition and reproductive success likely follows a nonlinear saturation function with a maximum optimal threshold (Harder and Thomson 1989).…”

“…Counting only viable pollen grains, by assessing pollen tube growth, has been effectively used for massblooming almond to look at pollinator performance, but such methods require specialized equipment and skill (Brittain et al 2013). Here, we employ an alternative method that experimentally establishes relationships between stigmatic pollen deposition and fruiting response (Cane and Schiffhauer 2003). Ne'eman et al (2010) distinguish a pollinator's ability to transfer pollen from its ability to initiate a fruiting response as per-visit effectiveness and efficiency, respectively.…”

Impact d’un apport supplémentaire de pollen sur la mise à fruit de Sambucus nigra subsp. canadensis (L.) R. Bolli

“…Ce niveau est habituellement moindre chez d'autres espèces ligneuses comme le bleuet en corymbe et la canneberge (60 à 80 %), le raisin (35 %), la pomme et la poire (3 à 20 %) (Dogterom et al 2000;Sampson et al 2001;Cane et Schiffhauer 2003;Kozma et al 2003).…”