An inverse latitudinal gradient in intraspecific genetic diversity of a dominant ant in the neotropical savanna

Abstract Although latitudinal gradient of diversity (LGD) is a biogeographic pattern widely shown for distinct animal groups, some display the opposite pattern, with biodiversity peaking away from the equator. These inverse gradients may result from drivers that also overlap with extrinsic factors shaping genetic diversity across taxa, a level of biodiversity less investigated under the LGD lens. Recent studies have reported an inverse trend of LGD for ant species and food web diversity in the Neotropical Cerrado savanna. However, it is unclear whether latitudinal gradients in diversity translate across biological scales to the most fundamental level of biodiversity: intraspecific genetic diversity (iGD). Here, we investigated the latitudinal distribution of iGD in one of the most abundant ants in Cerrado: Camponotus crassus (Formicidae: Formicinae). We sampled workers from distinct Cerrado localities distributed across a latitudinal gradient and asked whether latitude, or any relevant abiotic and/or biotic factor, explained iGD. Workers were genotyped for single nucleotide polymorphisms, and iGD was evaluated against data for climate, ant community, availability of sugar‐rich resources, local abundance, and geographic distribution of C. crassus . Consistent with diversity across other scales, all iGD estimates increased significantly with latitude. iGD was negatively correlated with annual precipitation, potentially due to its role in regulating nuptial flights in ants. iGD also showed a positive correlation with sugar‐rich food availability, suggesting that access to key resources may influence demographic and evolutionary processes in ant populations. Our large‐scale work fills a knowledge gap of the patterns and drivers of ant diversity across dry and warm ecosystems in a dominant ant species. It suggests that an inverse LGD for ants is not restricted to species and ecological interaction levels, but also translates to the intraspecific level, adding a novel perspective to the current knowledge of ant biodiversity distribution in the Neotropics.