1. Carreck Consultancy Ltd., Shipley, West Sussex, UK;
2. Swiss Bee Research Center, Agroscope, Bern, Switzerland;
3. Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland;
4. Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland;
5. Department of Entomology and Nematology, University of Florida, Gainesville, FL, USA