When African and European Lineages Meet: The Genetic Landscape of Honey Bees in Argentina

Argentina has a complex and diverse landscape of honeybee (Apis mellifera sp.) populations shaped by historic introductions and hybridization between Africanized (AHB) and European (EHB) lineages. While a latitudinal cline of Africanization has been documented, the adaptive consequences of this genetic admixture and its implications for local beekeeping practices remain poorly understood. In this study, we provide a more in-depth analysis of Argentine honeybee populations using recently published data from a panel of 272 SNP markers across five ecoregions to: (1) quantify how ancestry proportion (African A, European C/M) varies along geographic gradients, (2) assess whether ecoregion boundaries influence population structure, and (3) evaluate the potential trade-offs between AHB and EHB ancestry in hybrid genomes. Our results confirm a strong latitudinal pattern of Africanization but reveal novel complexity, with C-lineage ancestry inversely correlated with A-lineage contributions while M-lineage ancestry remains independent. We also detected trace contributions from the O lineage (Middle Eastern), highlighting Argentina's complex admixture history. Despite Argentina's diverse ecoregions, we find limited evidence for ecotype-specific differentiation, suggesting gene flow may outweigh local adaptation-though sampling limitations warrant caution. By linking genetic patterns to apicultural relevance (e.g., AHB's northward expansion and hybridization zones), this study provides a framework for conserving genetic diversity and managing hive productivity across environmental gradients. Further genome-wide analyses are needed to disentangle adaptive traits in this understudied yet economically critical pollinator system.