Multiple independent origins of neoteny reveal convergent relaxation of mitochondrial selection in beetles

Mitochondrial genome evolution is shaped by organismal energy demands, with high-performance lineages typically showing stronger purifying selection on oxidative phosphorylation (OXPHOS) genes. We tested this relationship in Elateriformia beetles by analyzing 132 mitochondrial genomes from 15 families, categorizing species as heavily sclerotized active flyers (HARD), weakly sclerotized with reduced flight (WEAK), or sedentary larviform neotenic forms (NEOTENIC). PAML branch models revealed that