Comparing host-plant resistance to herbivory between domesticated and wild highbush blueberry populations in southern New Jersey

The effects of domestication on resistant traits against herbivory are poorly understood in general, and not at all for highbush blueberry (Vaccinium corymbosum). Theory predicts that selective breeding for increased growth and yield leads to negative tradeoffs in defense, and several studies support this (Benrey et al. 1998, Herms and Mattson 1992 , Mirnezhad et al. 2010, Rodriguez-Saona et al. 2011). V. corymbosum is one of the most economically important crops in New Jersey, totaling $62.5 million in 2010 (NASS 2010) and is native to the Pinelands region of the state. Pest management is handled overwhelmingly by the conventional application of insecticides, which is environmentally hazardous and concerning to consumers. However, the utilization of natural plant defenses in pest management has not been fully explored. This study addresses these questions: 1. Does arthropod community composition and performance differ between neighboring domesticated and wild populations? 2. Can this be explained by domestication status? 3. How variable are wild populations in composition and performance?

To answer them, we sampled insect communities on 15 paired populations of wild and domesticated V. corymbosum in the field. Under greenhouse conditions, we grew gypsy moth larvae (Lymantria dispar), and measured differences in insect growth and induced volatile emission. This will suggest future pathways for the study of underlying genetic mechanisms of resistance in V. corymbosum, and the results will be important for the selection of resistant traits against insect herbivores. Preliminary data show significant differences in insect community composition between wild and domesticated populations.