Downscaling plant-frugivore interaction networks in an assemblage of fig consumers

Abstract

Measuring interaction strength is key to understand the dynamics of mutualistic networks. However, how in-tiaspecrfic variation within species traits can affect the patterns and outcomes of an interaction has been poorly measured. In this study, we explored how individual variation in fruit production in a fig tree species influences fruit consumption by frugivorous birds. Degree, expressed as the number of bird species, and visitation rates, expressed as number of individuals and its equivalent biomass, were independent of crop size. However, the cumulative number of visits for the three variables mentioned above was proportional to crop size. The number of small bird species (<100 g) was twice that from large species. However, the biomass of both groups was equivalent. Fruit consumption, expressed both as intake rate and total intake, was proportional to bird bodv mass. Our results suggest that the interaction between birds and fig trees depends on the size distribution of both organisms and the forest successional stage. In addition, from the consumers' perspective, the amount of energy that each bird obtains depends on individual tree characteristics.