Chorthippus Alps (ticino) - genomic data

DOI: https://doi.org/10.1093/zoolinnean/zlaf076 || Clarifying diversity in the radiation of Chorthippus grasshoppers (Orthoptera: Acrididae) through an integration of genomic and morphometric approaches || Rapid species radiations driven by sexual selection present challenges to species delimitation due to limited ecological and morphological divergence among taxa. Combining multilocus genomic markers with morphometric analyses can provide insights into taxonomy and evolutionary history in such groups. We examine three grasshopper species of the genus Chorthippus, which radiated primarily through behavioral isolation via divergence in male calling songs, the main diagnostic species trait. Our study clarifies evolutionary relationships among five taxa classified by song: species (C. biguttulus, C. brunneus), subspecies (C. mollis mollis, C. mollis ignifer), and aberrant forms (C. brunneus ab. ticino). Morphometric analyses reveal that wing morphology follows the differentiation in male calling song, serving as proxy for distinguishing species groups. However, genomic analyses show greater divergence than expected between subspecies with the mollis song type and there seems to be cryptic diversity within C. mollis ignifer. Furthermore, local varieties with intermediate traits are genetically identical to C. brunneus, rejecting a hypothesis of hybrid origin. These findings demonstrate that song and wing morphology aid in delimiting taxa but are unreliable indicators of lineage diversity, underscoring the need for integrating genomic markers with morphometrics to understand the taxonomic and evolutionary history of radiations driven by sexual selection.