The Effect of Alien Plants on the Survival of Larval Lepidoptera

Abstract

The proliferation of alien plants and their widespread replacement of native plants is predicted to negatively affect the insect community. Conservation biocontrol seeks to protect natural enemies, such as predators and parasitoids, through methods such as habitat management, in which plants are used to provide necessary resources to natural enemies. Native plants may support a stronger population of natural enemies than exotic plants. Bagworm and polyphemus moth larvae were placed in alien and native plant plots, and their survival was tracked until pupation. It was predicted that plots planted with native plants would have enhanced natural enemy communities, resulting in increased mortality in caterpillar larvae. Thus, larval survival would serve as a relative measure of the natural enemy community in plots planted with alien plants versus plots planted with native plants. No difference was found between the survival of bagworm larvae between alien and native plots. Almost no difference was found in the survival of polyphemus larvae, though the polyphemus moth experiment may have been confounded by differing rates of growth based on food plant.