Tropical Ecology and Conservation [Monteverde Institute]

Alternative Title

Eficiencia de los polinizadores en Blakea gracilis (Melastomataceae)



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Publication Date

October 2008


Blakea gracilis (Melastomataceae) is one of 20,000 species of flowering plants whose flowers have poricidal anthers. This morphology is adapted for “buzz-pollination,” where bee-induced vibrations result in the expulsion of pollen through the anther pores. The frequency of vibrations significantly affects pollen release, with peak anther discharge occurring at 500 Hz. Bees, however, are only able to buzz at about 300 Hz, and rarely reach frequencies higher than 400 Hz. This gap leaves the potential for a “most efficient” pollinator, a particular bee able to buzz at the highest frequency, thereby procuring the most pollen per visit and moving more pollen from flower to flower. In this study, I aimed to determine whether a “most efficient” pollinator exists for Blakea gracilis. I focused on large-bodied bees and small-bodied bees, predicting that larger bees would be capable of reaching higher frequencies and therefore would be better pollinators than their smaller counterparts. I found that large- and small-bodied bees open the same number of anthers per visit (t = 0.553, df = 36.277, p = 0.584), even though small bees spend significantly more time buzzing each flower (t = 3.753, df = 22.5, p = 0.001). Large-bodied bees achieved the same success as their smaller counterparts in less time by opening more anthers per second (t = -3.266, df = 36.3, p = 0.002). Despite their length of visitation, the amount of time each size-class spent buzzing a flower did not affect how many anthers they opened (large-bodied: R2 = 0.061, p = 0.080, t = 1.786; small-bodied: R2 = 0.169, p = 0.057, t = 2.019). I found one exception in Bombus sp., which was able to open more anthers the longer it vibrated the flower (Spearman’s Rho = 0.576, p = 0.041, N = 10). I found that there is no “most efficient” pollinator of Blakea gracilis, instead the results are consistent with those of past studies which concluded that buzz-pollination is generalized to all bee visitors.


En este estudio, yo tenía como objetivo determinar si existe un polinizador más eficiente para Blakea gracilis. Me enfoqué en abejas grandes y pequeñas, prediciendo que las abejas grandes serían capaces de alcanzar frecuencias más altas y por lo tanto serían mejores polinizadores que sus contrapartes más pequeñas.


Pollination by bees, Flowers--Morphology, CIEE Fall 2008

Palabras claves

Polinizado por abejas, Flores--Morfología, CIEE Otoño 2008


8 pages

Geographic Location

Monteverde (Puntarenas, Costa Rica)

Holding Location

Monteverde Institute


English; Spanish

Media Type



Digital Only





Pollinator efficiency in Blakea gracilis (Melastomataceae), October 2008



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