1. Laboratory of Zoology, Research institute of Biosciences, University of Mons, Place du Parc 20, Mons B – 7000, Belgium
2. Department of Geography, University of Namur, Rue de Bruxelles 61, Namur B – 5000, Belgium
3. Research Unit Animal and Functionalities of Animal Products (URAFPA), University of Lorraine – INRA, 2 avenue de la Forêt de Haye, BP 172, Vandoeuvre-lès-Nancy F – 54505, France
4. Visiting Research Fellow, Reading University, Reading RG6 6AR, UK