Parasitism of light brown apple moth, Epiphyas postvittana, in California

The invasive leafroller Light Brown Apple Moth, Epiphyas postvittana (Lepidopter: Tortricidae), was discovered in California in 2006. Invasive species generally exhibit poor parasitoid complexes that are dominated by generalists and cause very low parasitism rates.  An extensive monitoring program for E. postvittana from 2008-2011 at four sites in California however showed that the parasitoid complex of this new invader was rich, dominated by specialists and causing high parasitism rates. However, further analyses showed that parasitism had no effect on E. postvittana population growth rates, but instead, strong negative density dependence was observed at all sites. Possible causes for this disconnect and the drivers of the negative density dependence are discussed.