Ant interactions with myrmechorous plants can range from predation to parasitism to dispersal. Some seed-dispersing ants are specialists, while others are generalists participating in a diffuse mutualism. Likewise, some seed predators are specialists that cache seeds, while others have a broader diet breadth. In longleaf pine forests, The Florida Harvester ant, Pogonomyrmex badius is a thoroughly studied seed predator. However, little is known about seed dispersers. In this study, we identify the ants species interacting with myrmechorous seeds in longleaf pine forests and determine whether they make-up a distinct subset of the ant community. Our research took place within longleaf pine sandhill habitat at Ordway-Swisher Biological Station (Melrose, FL). We employed three separate methods for ant species collection: leaf litter sifting, baiting with tuna and honey mixtures, and baiting with the myrmechorous seeds of the plant Rabbitbells, Crotalaria rotundifolia. To ensure our sampling adequately captured the diversity of ant species present in longleaf pine sandhill, we also identified ant species from National Ecological Observatory Network (NEON) ground beetle pitfall samples for comparison. Non-metric Dimensional Scaling and multivariate ANOVA was used to compare species composition across collection methods.
Results/Conclusions
We found that seed-removing ant species are a non-random subset of the ant community. About 40% of the total ant species detected across all methods were observed removing seeds. The species retrieving seeds were a unique and consistent subset of the species observed at tuna-honey baits. This suggests that these ants are generalists participating in a diffuse mutualism. Related research has indicated that these species are relatively resilient to prescribed fire; they nest below-ground, not in leaf litter. Neivamyrmex was the only ant genus found in NEON samples that was not collected by our three sampling methods. This is a genus of specialist carnivores called army ants, which raid brood from other ants’ nests. Identification of seed-dispersing ants and assessing their resiliency to fire is an important step in discerning the role of ant community composition in plant community structure in longleaf sandhill, an ecosystem managed with prescribed fire for high biotic diversity.