Abstract
Every year more than one million commercial bumblebee colonies are deployed in greenhouses worldwide for its pollination services to several commercially important crops such as tomato and different species of berries. While commercial pollinators have been an enormous benefit for the production of essential food crops and for achieving higher yields and better fruit quality at a low cost, their use is emerging also as an important threat to wild pollinators. Commercial pollinators have been linked to pathogen spillover to wild species, and its introduction outside its native area have had devastating effects on native pollinator populations. However, a more pervasive, but underappreciated threat is their potential impact on the genetic integrity of native pollinators. Here, we show clear evidence of generalized hybridization between native and introduced commercial bumblebee lineages in southern Spain. The signal of genetic introgression is widespread and already expands up to 60 km from main commercial bumblebee release areas. As pollination services demand is predicted to increase in the coming years, only a more restrictive regulation of commercial lines could mitigate their negative impacts on the genetic integrity of native pollinators and prevent the disruption of local adaptations.
