1. Department of Biology, University of Lund, Helgonavägen 3, 223 62 Lund, Sweden
2. Ecophysiological Studies Research Group, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Wits 2050, South Africa
3. Department of Zoology and Entomology, University of Pretoria, Pretoria 0001, South Africa