POPULATION ECOLOGY Host Pubescence and the Behavior and Performance of the Butterfly Papilio Troilus (Lepidoptera: Papilionidae)

We found that leaf pubescence in Sassafras albidum (Nuttall) Nees negatively inßuences the growth and survivorship of a lepidopteran herbivore, Papilio troilus (L.). S. albidum leaves varied greatly in pubescence among plants. In laboratory choice experiments, P. troilus larvae preferred to eat and adult females preferred to oviposit on nonpubescent S. albidum leaves. Larvae fed pubescent S. albidum had slower growth and higher mortality in early instars than larvae fed on nonpubescent leaves. These negative effects of pubescence on adult oviposition, larval growth rate, and larval survivorship suggest that the population size of P. troilus will reßect availability of nonpubescent hostplants. In Þeld surveys, the frequency of pubescent S. albidum was signiÞcantly greater in open habitats created by harvesting pine forest than in hardwood forests, perhaps because of higher light and lower moisture in open areas. By changing the availability of quality food resources, forest management may have unintended negative impacts on this butterßy population.