1. The University of Queensland, School of Animal Studies, Warrego Highway, Gatton QLD 4343
2. National Wildlife Research Centre, 4101 LaPorte Avenue, Fort Collins, CO 80521-2154, USA (Richard.M.Engeman@aphis.usda.gov)
3. Biosecurity Queensland, Robert Wicks Pest Animal Research Centre, Tor Street, Toowoomba, QLD 4350 (Lee.Allen@deedi.qld.gov.au)