Poster and research information:

Many plant species produce EFNs, which are commonly associated with defensive mutualisms. In quaking aspen, a subset of leaves express EFNs where the base of the leaf meets the petiole. In the past decade, the ALM has caused extensive damage to aspen in Alaska. Adult ALM moths feed on nectar secreted by aspen EFNs and lay eggs (oviposit) on aspen leaves. ALM larvae chew serpenDne mines through the epidermal cell layers of the leaf and pupate on the leaf edge before emerging as adult moths. Damage from ALM mining reduces aspen growth, and causes early leaf abscission and reduced photosynthesis.

Predacious arthropods such as ants, parasitoid wasps, and mites also feed on nectar at aspen EFNs, and have been shown to reduce ALM damage. However, mining damage is consistently lower on leaves with EFNs even under predator exclusion. The purpose of this study is to test a hypothesis for the lower mining damage observed on leaves with EFNs. Because the risk of larval ALM mortality might be greater on leaves with EFNs, we predicted that ALM moths prefer to oviposit on leaves without EFNs.

In the summer of 2009, we conducted experiments to test ALM oviposition site preference between leaves with and without EFNs. We offered gravid female moths one of each leaf type and recorded on which leaf the first egg was laid and how many eggs were laid on each leaf type. Females tended to choose leaves without EFNs for their first egg, and also laid more eggs on these leaves. These results suggest EFN-mediated ALM oviposition site preference. We will further investigate these trends under natural conditions and include larval survivorship as a proxy for fitness to support the preference hypothesis.