Interaction frequency as a surrogate for the total effect of animal mutualists on plants

We evaluate whether species interaction frequency can be used as a surrogate for thetotal effect of a species on another. Because interaction frequency is easier to estimatethan per-interaction effect, using interaction frequency as a surrogate of total effect couldfacilitate the large-scale analysis of quantitative patterns of species-rich interactionnetworks. We show mathematically that the correlation between interaction frequency(I ) and total effect (T ) becomes more strongly positive the greater the variation of Irelative to the variation of per-interaction effect (P) and the greater the correlationbetween I and P. A meta-analysis using data on I, P and T for animal pollinators and seeddispersers visiting plants shows a generally strong, positive relationship between T and I,in spite of no general relationship between P and I. Thus, frequent animal mutualistsusually contribute the most to plant reproduction, regardless of their effectiveness on aper-interaction basis.Fil: Vázquez, Diego Eduardo. Centre d’Ecologie Fonctionnelle et Evolutive; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; Argentina. University of California; Estados UnidosFil: Morris, William F.. University of Duke; Estados UnidosFil: Jordano Barbudo, Pedro. Consejo Superior de Investigaciones Científicas. Estación Biológica de Doñana; Españ