Patterns of virus coincidence between honey bees and bumble bees in the Pacific Northwest, USA

Many viruses first isolated in honey bees can also infect and circulate in wild bee species. While most common bee viruses are generally less prevalent in wild bees than honey bees, they are occasionally locally common. However, most studies have not assessed prevalence of viruses in honey bees and wild bees at the same sites, making it difficult to determine how viruses may spread across species. We addressed this by surveying the prevalence of six viruses in honey bees and bumble bees at sites across the Pacific Northwest, USA. These data were used to assess covariance in virus prevalence between bee groups across multiple ecotypes and to assess how virus prevalence in bumble bees correlated with prevalence in honey bees. We show deformed wing virus (DWV) and black queen cell virus (BQCV) were more common in honey bees than bumble bees, while Israeli acute paralysis virus (IAPV) was found at similar levels. Prevalence of DWV and IAPV were correlated with landscape context, with both most common at urban sites. However, BQCV prevalence in bumble bees was best predicted by BQCV prevalence in honey bees and by apiary density. Our study provides evidence that several viruses are found in both honey bees and wild bumble bees at the same sites, although prevalence was not necessarily correlated among the two groups. Understanding the prevalence and impacts of bee viruses on both managed and wild bees is key for disease mitigation and pollinator conservation.