Assistant Professor University of Nevada Reno, Nevada
Plants are the foundations of communities, interacting with a diversity of herbivores, pollinators, and higher trophic levels through complex networks of interactions. Plants use a broad array of physical and chemical traits to direct these interactions, which can have major fitness consequences. Variation in plant phenotypes is important to both the strength and quality of individual interactions and community structure more broadly. Herbivore community assembly is known to be shaped by heritable plant traits (including chemistry, which can vary across the landscape). However, much of the work investigating how plant defensive chemistry mediates interactions with herbivores has focused on single herbivore species or simple communities. Our understanding of how chemical diversity within natural plant populations shapes interactions with diverse herbivore communities via plant chemistry is less well understood. Here, we use a Great Basin specialist shrub Ericameria nauseosa (rubber rabbitbrush) and its diverse and variable community of gall forming insects (Cecidomyiidae and Tephritidae) to investigate whether fine-scale patterns of plant chemical diversity influence diversity and abundance of specialist herbivores. Using GC-MS methods and a K-means cluster analysis we identified 6 shrub chemotypes within a large natural Rabbitbrush population in the Virginia Mountains, Nevada. In order to understand how herbivore communities vary with plant chemical diversity, gall species composition and abundance were quantified for twenty replicates from each chemotype. Further chemical analyses (GC-MS and LC-MS) were used to investigate tissue-specific plant chemistry. Together these data provide a detailed picture of the importance of plant phenotypic variation in shaping specialist herbivore communities.
