Within- 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 significant difference occurred among populations in host-plant preference. Differences in host-plant preference existed among female moths within a population, and these differences are under genetic control and heritable. Most females ranked maize, sorghum and tobacco highest, followed by cotton varieties DP90 and HG660. The least-preferred plants were cowpea and lucerne. A few females (20%) differed from this general pattern and among each other, and reversed the rank order of host plants. Within a population, individual female moths differed in their host-plant specificity, with some individuals being more generalist than others. Similarly, significant differences occurred in host-plant specificity among populations. The relevance of these findings are discussed in relation to polyphagy in H. armigera.