1. Center of Chemical Ecology; Entomology Department; The Pennsylvania State University; University Park Pennsylvania 16802 USA
2. Pharmaceutical Biotechnology; Martin Luther Universität; Halle (Saale) D-06120 Germany
3. Mathematics Department; Bucknell University; Lewisburg Pennsylvania 17837 USA
4. Division of Applied Biosciences, Graduate School of Agriculture; Kyoto University; Kyoto 606-8502 Japan