Impacts of a DNA virus, an adjuvant, and their interaction on development, survivorship, and immune responses in the blue orchard bee (Osmia lignaria Say, Hymenoptera: Megachilidae)

Many viruses studied in bee health surveys are RNA viruses, whereas DNA viruses lack thorough investigation and are often overlooked in bee pathogen surveys and studies. Apis mellifera filamentous virus (AmFV) is a double-stranded DNA virus first described from Apis mellifera. In recent years, AmFV has been found in solitary bee populations. Our current research shows that AmFV is a prolific virus persisting in wild and managed Osmia lignaria populations. In our pilot study, we found that a high dosage of AmFV significantly decreased survival of O. lignaria Iarvae. In a follow-up study, we combined a medium concentration of AmFV with 100 parts per million of an adjuvant (organosilicon surfactant). We did not find a synergistic interaction on survival and development. In the future, we will assess immune gene expression to investigate the underlying mechanisms concerning how AmFV impacts O. lignaria development and survival.