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

Abstract We evaluate whether species interaction frequency can be used as a surrogate for the total effect of a species on another. Because interaction frequency is easier to estimate than per‐interaction effect, using interaction frequency as a surrogate of total effect could facilitate the large‐scale analysis of quantitative patterns of species‐rich interaction networks. We show mathematically that the correlation between interaction frequency ( I ) and total effect ( T ) becomes more strongly positive the greater the variation of I relative to the variation of per‐interaction effect ( P ) and the greater the correlation between I and P . A meta‐analysis using data on I , P and T for animal pollinators and seed dispersers 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 mutualists usually contribute the most to plant reproduction, regardless of their effectiveness on a per‐interaction basis.