1. Laboratory of Functional Morphology, Department of Biology, University of Antwerp, Universiteitsplein, Wilrijk, Belgium
2. Theoretical Ecology Group, Department of Mathematical Sciences, Stellenbosch University, Private Bag, Matieland, Stellenbosch, South Africa
3. Department of Botany & Zoology, Stellenbosch University, Private Bag, Matieland, Stellenbosch, South Africa
4. Theoretical and Physical Biosciences, African Institute for Mathematical Sciences, Cape Town, South Africa