Mitochondrial genome and <i>cox1</i> diversity of the European orchard bee

The subgenus Osmia (Osmia) consists of solitary bees belonging to the family Megachilidae, currently comprising 29 species distributed throughout the Holarctic region. Among them, O. cornuta is one of the most studied and successfully managed species in Europe for orchard pollination. Despite its potential as an efficient pollinator, O. cornuta faces stressors such as urbanization, agrochemical exposure and climate change, which may impact its health and behaviour and thus its ecological role. Additionally, recent reports show that O. cornuta has been introduced in North America, raising concerns about its potential ecological impact in the new environment. In this study, we obtained the first mitochondrial genome of O. cornuta from specimens collected in northern Italy. The overall characteristics of the mitogenome were comparable to those of other Osmia species, and comparison with all available megachilid mitogenomes revealed genus- and family-level gene rearrangements. Phylogenetic analyses confirmed the position of O. cornuta, while intra-specific genetic variability based on mitogenomes from 20 individuals sampled in northern Italy indicated low genetic divergence among the sampled bees. Similarly, analysis of all available cox1 sequences suggested the absence of geographic structuring across the native range of the species. Our findings provide a valuable resource for future studies on O. cornuta, contributing to a better understanding of its genetic diversity, potential introduction routes, and implications for conservation and pollination services.