Assessing the potential for indirect interactions between tropical tree species via shared insect seed predators

Natural enemies of plants have the potential to influence the dynamics of plant populations and the structure of plant communities. In diverse tropical forests, research on the effects of plant enemies has largely focused on the diversity-enhancing effects of highly specialized enemies, while the community-level effects of enemies with broader diets have rarely been considered. We investigated the community of insect seed predators interacting with seven tree species in the family Lauraceae on Barro Colorado Island (Panama). We present one of the first quantitative food webs for pre-dispersal insect seed predators and their host plants, and use the information in the web to assess the potential for indirect interactions between the tree species. Our data suggest that there is high potential for indirect interactions between Lauraceae species via their shared seed predators. The strength and direction of these interactions are largely unrelated to the phylogenetic distance and trait similarity between species but are likely governed by the volume of fruit produced by each tree species.