1. Institute of Integrative Biology; ETH Zürich; Zürich Switzerland
2. EAWAG; Swiss Federal Institute of Aquatic Science and Technology; Dübendorf Switzerland
3. Current address: Unit of Evolutionary Biology and Systematic Zoology, Institute of Biochemistry and Biology; University of Potsdam; Potsdam Germany
4. Department of Entomology; University of Georgia; Athens Georgia 30602