WITHIN-POPULATION AND BETWEEN-POPULATION VARIATION IN HOST-PLANT PREFERENCE AND SPECIFICITY IN AUSTRALIAN HELICOVERPA-ARMIGERA (HUBNER) (LEPIDOPTERA, NOCTUIDAE)

Using a tethered-insect technique, we investigated within- and between -population variation in the post-alighting host-plant preference and specificity of female Helicoverpa armigera from four populations. No s ignificant difference occurred among populations in host-plant prefere nce. Differences in host-plant preference existed among female moths w ithin a population, and these differences are under genetic control an d heritable. Most females ranked maize, sorghum and tobacco highest, f ollowed by cotton varieties DP90 and HG660. The least-preferred plants were cowpea and lucerne. A few females (20%) differed from this gener al pattern and among each other, and reversed the rank order of host p lants. Within a population, individual female moths differed in their host-plant specificity, with some individuals being more generalist th an others. Similarly, significant differences occurred in host-plant s pecificity among populations. The relevance of these findings are disc ussed in relation to polyphagy in H. armigera.