Spatiotemporal niche-based mechanisms support a stable coexistence of ants and spiders in an extrafloral nectary-bearing plant community.

Mechanisms promoting stable coexistence allow multiple species to persist in the same trophic level of a given network of species interactions. One of the most common stabilizing mechanisms of coexistence is niche differentiation, such as temporal and spatial patchiness. To understand the limits of coexistence between species we have to understand the limits of competitive interactions which translate in species exclusion or patterns of non-co-occurrence. We evaluated spatiotemporal niche-based mechanisms that could promote stable coexistence between ants and spiders which forage on extrafloral nectary (EFN)-bearing plants. We observed co-occurrence and overlapping patterns between ants and spiders in a temporal and spatial scale in nine different EFN-bearing plant species in a Neotropical savanna, using both community and species-level approach. Ants and spiders showed asynchrony of their abundances over the year with low temporal overlapping patterns between them (temporal niche specialization). Greater abundance of ants occurred between September and March, whereas greater abundance of spiders occurred between March and August, exactly at the time when the abundance of ants decreases on plants. However, there might also be some levels of temporal overlapping, but then individual ants and spiders occupy different branches (spatial segregation). Finally, we also observed a spatial negative effect of the abundance of ants on the presence of spiders. Our results suggest that spatiotemporal partitioning between ants and spiders may be one of the potential mechanisms behind a stable coexistence between these two groups of organisms that forage on EFN-bearing plants in the Brazilian savanna.