Morphometric changes in wings of bess beetles (Coleoptera: Passalidae) related to elevation: a case of study in the Colombian Andes

Flight is a crucial evolutionary novelty for insect diversification. Despite its importance, some insects lose this ability. Flight loss is related to the reduction in the veins and membrane of hind wings (brachypterism), often related to high elevations. Brachypterism evolved independently in some lineages of beetles, like in the family Passalidae. Due to the double function of the passalid hind wings (dispersion and acoustic communication), the wing reduction process is partial and apparently constrained by the stridulatory apparatus. The tribe Proculini is a good model to study brachypterism due to the number of flightless species and its distribution between low land and high montane ecosystems. We evaluated the relationship between wing reduction and elevation in the elytra and hind wings of 25 Proculini species distributed in Colombia, using linear measurements and geom-25etric morphometry. Specimens were categorized in three elevation ranges: low (0-999 m), middle (1000-1999 m), and high (<2000 m). In conclusion, this study demonstrates that elevation is most likely the factor that has driven size and shape modifications of the Passalidae hind wings and elytra. The present work is the first study that tests the relationship between brachypterism and elevation using Proculini species belonging to different genera.