Is there genetic structure in populations of Helicoverpa armigera from Australia?

Recent studies suggest that populations of the pest moth Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) may be genetically differentiated over short distances and time periods within Queensland, Australia. To test for genetic structure in another region of Australia, we characterized population differentiation in Victorian samples of H. armigera using eight microsatellite loci. We found no evidence of genetic structure among samples from different locations or among samples collected at different times. Moreover, Victorian samples were not differentiated from other samples of H. armigera from Queensland and New Zealand. All samples showed substantial deviations from Hardy-Weinberg equilibrium, suggesting a high frequency of null alleles typically found in microsatellites of Lepidoptera. These results indicate that populations of H. armigera are not strongly structured among regions in south-eastern Australia.