The evolution of South American populations of Trimerotropis pallidipennis (Oedipodinae: Acrididae) revisited: Dispersion routes and origin of chromosomal inversion clines

Abstract

In the past few years large-scale genome sequencing has demonstrated that inversion rearrangements are more frequent than initially hypothesized. Many examples suggest they may have played an important function in delineating the evolution of biodiversity. In particular, clinal patterns of variation for this type of rearrangement point out its significance in relation to the evolution and adaptation of organisms to changing environments. Within grasshoppers, Trimerotropis and Circotettix show high incidence of inversion rearrangements, either in fixed or polymorphic state, according to which several hypotheses about phylogenetic relationships have been proposed. Herewith we review the evolutionary significance of inversions in Trimerotropis pallidipennis, whose South American populations show clinal variation for pericentric inversions along environmental gradients. We report a new phylogeographic analysis that includes populations of this species from North and South America, and also other species of Trimerotropis and Circotettix. This study was performed in order to gain further insights into the phylogenetic relationships of this group of species, the dispersion routes followed by T. pallidipennis in South America and the evolutionary significance of inversion clines.