Climatic adaptation of the widespread ant species Formica podzolica: A landscape genomics approach

Many ant species span broad environmental gradients, but changing climates can alter the suitability of regions and, in some cases, surpass ants’ physiological limits. The discord between environment and physiology can cause shifts in species ranges, decreases in populations, or even extinction. The adaptive capacity of a species can, in part, determine the difference between these evolutionary outcomes; those that have genetic variation for climate-related traits are most likely to have the capacity to adapt to rapidly transforming environments. Understanding the consequences and distributions of potentially adaptive alleles corresponding to climate can, therefore, illuminate causes of ants’ widespread ecological success and broad species ranges, as well as aid efforts to accurately predict species responses to future conditions. A particularly widespread ant species is Formica podzolica, which lives across a ~3000-meter elevation range throughout the Rocky Mountains from Canada to New Mexico. The large latitudinal and elevational gradient of F. podzolica raises the question: Do F. podzolica have adaptive genomic regions that allow them to be uniquely suited for the broad range of environments they inhabit? To investigate this question, we employ landscape genomic and species distribution modeling techniques. Identifying genomic signatures of adaptation in F. podzolica allows us to better understand the ecological success of this widespread, native, socially polymorphic ant species existing within extreme environmental heterogeneity. Further, it informs us about the adaptation ability of the genus as a whole across North America and opens the door for predictions of how these ants will respond to climate change.