Can variation in seed removal patterns of Neotropical pioneer tree species be explained by local ant community composition?

Many plants depend on animals for seed dispersal, and ants commonly fill this role. We examined whether heterogeneity in ant community composition among sites, between above- and belowground foraging guilds, or between seasons predicts observed variation in seed removal rates for 12 nonmyrmecochorous Neotropical pioneer tree species on Barro Colorado Island, Panama. We also investigated whether ants associated with removing seeds differed in specific morphological characters from the larger ant community. We observed ant–seed interactions at caches to determine which ants removed seeds of 12 tree species. We also sampled ant community composition by placing 315 pitfall traps and 160 subterranean traps across the five sites where seed removal rates were quantified. Aboveground ant community composition varied by site but not season. Among-site variation in ant composition did not predict seed removal patterns at these same sites. Belowground ant communities differed from aboveground ant communities but were not structured by either site or seed cache type. Finally, ants that removed seeds did not differ morphologically from the broader ant community. Overall, our results suggest ant communities vary over relatively small spatial scales but exhibit a high degree of functional redundancy in terms of seed removal services provided for Neotropical pioneer tree species. Abstract in Spanish is available with online material.