Author: Hendrik Segers Affiliation: Laboratory of Animal Ecology, Zoogeography and Nature Conservation, Department Biology, University of Gent, K. L. Ledeganckstraat 35, B-9000 Gent, Belgium; Niniver L Ferrufino Affiliation: Unidad de Limnología y Recursos Acuáticos, Universidad Mayor de San Simón, Casilla 5263, Cochabamba, Bolivia; Luc de Meester Affiliation: Laboratory of Ecology and Aquaculture, Katholieke Universiteit Leuven, Naamsestraat 59, B-3000 Leuven, Belgium