1. INRAE, Abeilles et Environnement, Avignon, France
2. Research Institute for Biosciences, Laboratory of Zoology, University of Mons, Place du Parc 20, 7000 Mons, Belgium
3. Council for Agricultural Research and Economics—Agriculture and Environment Research Centre, Via di Corticella 133, 40128 Bologna, Italy
4. Institute for Sustainable Plant Protection, National Research-Council, Piazzale Enrico Fermi 1, 80055 Portici, Naples, Italy
5. Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland