Trouble in the tropics : pathogen spillover is a threat for native stingless bees

Abstract

Pathogen spillover is a major threat to biodiversity. Insect pollinators, important providers of the ecosystem service of pollination that are in global decline, are no exception to this threat, with mounting evidence of pathogen spillover from managed into wild bee species in temperate regions. The phenomenon is likely global in scope, though poorly documented, and its consequences for recipient species are largely unknown. To address these knowledge gaps, we investigated viral spillover in the neotropics from the honey bee (Apis mellifera), where it is a managed and invasive species, into native stingless bees, a biodiverse taxon of pollinators. We furthermore exposed stingless bees to honey bee viruses to test for their impact on host survival. High viral prevalence in honey bees and low prevalence of identical viral haplotypes in stingless bees supports ongoing spillover from managed to native species. The survival of native stingless bees was reduced when inoculated with virus by feeding, a plausible route of natural infection. We conclude that viral spillover from managed to wild insect pollinators is likely a global phenomenon and poses a serious threat worldwide to native insect species. If negative impacts are detected in the field, conservation management needs to be developed to reduce spillover, including better control of pathogens in managed species and legislation on their movement.