Israeli acute paralysis virus (IAPV) affects commercially-managed non-Apis pollinators

Bees are intensely managed animals, given their pollination services; however, the stresses of intense management predisposes them to a variety of disease pathogens. RNA viruses, including a recently-described Israeli acute paralysis virus (IAPV), are linked to honey bee (Apis mellifera) colony losses worldwide, but our knowledge of viral diseases in other managed bee species is very limited. Bioassays were conducted to study the impact and related pathology of IAPV in two major non-Apis commercial pollinators, the alfalfa leafcutting bee (ALCB) (Megachile rotundata), an essential pollinator of the alfalfa seed crop, and the bumble bee (Bombus impatiens), the main pollinator of greenhouse crops. When IAPV was fed to virus-free ALCB larvae, bee diapause was disrupted, resulting in loss of bees available for next season. IAPV infection significantly reduced the ALCB adult survivorship when acquired as newly emerged adults. Virus replication was confirmed in both adult and larval stages of ALCB, but the infection was confined to the gut in larvae. Bumble bee colony survival and foraging activity was reduced by IAPV infection under greenhouse conditions. Virus was detected in different tissues of bumble bee adults away from the gut, indicating the dissemination of virus. These results indicate that RNA viruses can infect and adversely impact non-Apis pollinators. To our knowledge, this is the first report on the pathology of IAPV in non-Apis bee species.