Host Plant Flowering Increases Both Adult Oviposition Preference and Larval Performance of a Generalist Herbivore

Most adult Lepidoptera feed on nectar, whereas caterpillars consume mainly structural tissue such as leaves, stems, flowers, and/or fruits. This may result in behavioral trade-offs in which search time for high-quality oviposition sites suitable for larval food is restricted by adult foraging needs. Here we report on the preference for and performance on flowering and nonflowering host plants of the generalist herbivore Helicoverpa armigera to explore whether there are such behavioral trade-offs between moth and their caterpillars offpsring. We found that the adult moths have a strong oviposition preference for flowering tobacco and sunflower plants. Young caterpillars preferred to feed on the inflorescences. Adult-realized fecundity was almost 10 times higher when ovipositing on flowering plants. Weight at pupation, which is correlated with potential future fecundity of the caterpillars, was also higher when feeding on flowers. We found no evidence for a behavioral trade-off and conclude that a general preference for flowers by Helicoverpa armigera is highly beneficial from a nutritional perspective for both adults and larvae. The results suggest that the manipulation of flowering plants for the attraction of oviposition is relevant to pest control of this polyphagous species.