Parental Effects of Diet in Fall Webworm

The environment or experiences of a parent generation can impact the fitness of the next generation, a phenomenon known as parental effects. Specialists are widely the focus of study of parental effects, and much less is known about whether parental effects are important in generalists. We investigated if the fitness of the offspring of generalist fall webworm (Hyphantria cunea, hereafter FW) was dependent on the host plant on which the parental generation was reared. We used four different host plants to rear FW larvae, two of which were high-quality hosts (chokecherry and black willow) and two were low-quality hosts (narrowleaf cottonwood and thin-leaf alder). We mated FW male and female moths that had both been reared on the same host plant as larvae (e.g. chokecherry) and created at least 9 maternal lines per host plant species. The resultant egg clusters were divided into four, so that a portion of each egg cluster was reared on one of the four host plants. Thus, we have larvae from each maternal line that are being reared on the parental host as well as 3 unfamiliar hosts; we are currently rearing them in the lab to pupation. To measure fitness, we will weigh the pupae and compare the data across the host plant groups. This project will help us understand whether parental effects in FW are present and if FW fitness in an environment can become anticipatory if we know the environment of the parental generation.