Schläppi D, Institute of Bee Health, Vetsuisse Faculty, University of Bern, 3097 Bern, Switzerland.
Chejanovsky N, Institute of Bee Health, Vetsuisse Faculty, University of Bern, 3097 Bern, Switzerland;  Department of Entomology, Agricultural Research Organization, Volcani Center, 50250 Bet Dagan, Israel.
Yañez O, Institute of Bee Health, Vetsuisse Faculty, University of Bern, 3097 Bern, Switzerland; Swiss Bee Research Centre, Agroscope, 3097 Bern, Switzerland.
Neumann P. Institute of Bee Health, Vetsuisse Faculty, University of Bern, 3097 Bern, Switzerland; Swiss Bee Research Centre, Agroscope, 3097 Bern, Switzerland.

Emerging infectious diseases are often the products of host shifts, where a pathogen jumps from its original host to a novel species. Viruses in particular cross species barriers frequently. Acute bee paralysis virus (ABPV) and deformed wing virus (DWV) are viruses described in honey bees (Apis mellifera) with broad host ranges. Ants scavenging on dead honey bees may get infected with these viruses via foodborne transmission. However, the role of black garden ants, Lasius niger and Lasius platythorax, as alternative hosts of ABPV and DWV is not known and potential impacts of these viruses have not been addressed yet. In a laboratory feeding experiment, we show that L. niger can carry DWV and ABPV. However, negative-sense strand RNA, a token of virus replication, was only detected for ABPV. Therefore, additional L. niger colonies were tested for clinical symptoms of ABPV infections. Symptoms were detected at colony (fewer emerging workers) and individual level (impaired locomotion and movement speed). In a field survey, all L. platythorax samples carried ABPV, DWV-A and -B, as well as the negative-sense strand RNA of ABPV. These results show that L. niger and L. platythorax are alternative hosts of ABPV, possibly acting as a biological vector of ABPV and as a mechanical one for DWV. This is the first study showing the impact of honey bee viruses on ants. The common virus infections of ants in the field support possible negative consequences for ecosystem functioning due to host shifts.