Pleistocene climatic oscillations influenced the emergence of geographically widespread and restricted genetic lineages in an Andean grasshopper species group.

The article focuses on the genetic diversification and environmental niche differentiation within the Trimerotropis pallidipennis species complex, a group of Andean grasshoppers distributed across South America. Using mitochondrial COI sequences, thousands of single nucleotide polymorphisms (SNPs), and ecological niche modeling, the study identifies at least five genetic lineages—three widely distributed and two geographically restricted—whose diversification was influenced by Pleistocene climatic oscillations and glacial refugia along the Andes. Notably, one lineage, referred to as Trimerotropis sp., exhibits chromosomal inversion polymorphisms associated with adaptation to more temperate habitats and a distinct ecological niche compared to sister lineages T. andeana and T. ochraceipennis. The findings suggest that historical climatic changes and geographic isolation shaped the evolutionary history and current distribution of these grasshoppers, with chromosomal inversions potentially facilitating adaptation and speciation within the complex.