Tage der Biodiversität 2027

Ultraviolet (UV) wing patterns are widely regarded as important visual signals in butterfly mate recognition and species discrimination. It has been suggested that, in regions where closely related species co-occur, natural selection favours divergence in UV wing patterns through character displacement to reduce the risk of interspecific mating and hybridization. We tested this hypothesis in butterflies of the genus Gonepteryx, using a large dataset of 683 samples that includes all 16 species and a majority of the recognized subspecies. To elucidate the evolutionary trajectory of these patterns, we first reconstructed a multi-gene, time-calibrated phylogeny for the group and used wing UV patch measurements to reconstruct the ancestral state. We further investigated genetic divergence in mitochondrial COI barcodes within and between Gonepteryx species to verify their taxonomic status. Comparing the structural UV wing patterns of species pairs occurring in sympatry across their geographic distributions, we found that, in all cases but one, co-occurring species exhibited distinct UV patterns, consistent with the prediction of character displacement. However, these patterns were also distinct where the same species did not occur together, so the observed differences could not be attributed specifically to present-day sympatry or to selection for reproductive character displacement. Reconstruction of the ancestral state indicated that the ancestor possessed a moderately sized UV-reflective area on both forewings and hindwings. We also found a significant correlation between UV pattern variability and the number of species inhabiting an area. Overall, our findings do not support the hypothesis that structural UV wing patterns in Gonepteryx are shaped by mate recognition-driven character displacement to avoid hybridization; instead, they suggest that the evolution of these hidden structural signals reflects broader patterns of species divergence unrelated to sympatric interactions.