1. Department of Entomology College of Plant Protection China Agricultural University Beijing 100193 China
2. Centre for Invasion Biology Department of Mathematical Sciences Stellenbosch University Matieland 7602 South Africa
3. Mathematical and Physical Biosciences African Institute for Mathematical Sciences Muizenberg 7945 South Africa
4. Departments of Plant Sciences and Biological and Agricultural Engineering University of California, Davis Davis California 95616 USA
5. School of Mathematics Hefei University of Technology Hefei 230009 China
6. School of Veterinary Medicine University of California, Davis Davis California 95616 USA
7. Laboratory of Entomology and Agricultural Zoology School of Agricultural Sciences University of Thessaly Thessaly 38446 Greece
8. Department of Entomology University of California Davis California 95616 USA
9. Center for the Economic and Demography of Aging University of California Berkeley California 94720 USA