PARENT SESSION
Poster Session # 19: Insect and Invertebrate Ecology.
Thursday, August 7 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
The ecological impact of variation in host plant quality on the geometrid herbivore, Epimecis hortaria.
Kluger, Emily*,1, Niesenbaum, Richard1, 1 Muhlenberg College, Allentown, PA
ABSTRACT- The aim of this study has been to assess how the geometrid herbivore, Epimecis hortaria, responds to different levels of plant defensive chemistry and leaf nutritional quality that vary with light environment and leaf age in populations of the host plant Lindera benzoin. Leaf chemical analysis has revealed wide variation in plant volatile chemistry and leaf nitrogen concentration in the host plant populations. Here we report on how E. hortaria, the primary herbivore in these populations, responded to this variation. Field feeding trials showed that E. hortaria consuming leaves with a greater proportion of volatile chemicals and lower nitrogen concentrations actually gained more weight and consumed less plant material than those feeding on leaves with less volatiles and more nitrogen. Those herbivores that gained weight more rapidly also had faster developmental and pupation rates. Dry weight measurements indicate that weight gain was independent of water retention by caterpillars. Because individuals feeding on plants with a greater proportion of volatile chemicals may be at greater risk of attack by parasitoids, rapid development on this food source may be adaptive. Variation in rates of attack by parasitoid wasps, the interaction of host plant leaf nitrogen content and volatile chemistry on feeding rates and herbivore population biology, and the potential for nitrogenous plant defensive compounds and their detoxification by E. hortaria are considered.
Key words: insect ecology, host plant quality, herbivore, parasitoid