Population Dynamics of Browntail Moth in North America

University Of Massachusetts Amherst, Amherst MA

Investigators

Abstract

Invasions of exotic organisms have disrupted many biotic communities worldwide. A unique example of an invasion that has undergone a reversal for unknown reasons is that of the browntail moth, Euproctis chrysorrhoea, that was accidentally introduced to North America near Boston from Europe in 1897. It became an important defoliator of many tree species throughout New England and was also a human health hazard due to severe skin rashes caused by irritating hairs from the larvae. Beginning around 1915, however, browntail populations receded gradually to coastal enclaves at the tip of Cape Cod and on islands in Casco Bay in Maine, where high densities have persisted ever since. Little research of any kind has been done on browntail moth in North America and no studies have explained why it declined and why it persists in coastal enclaves. In recent years the populations in Casco Bay have expanded once more onto adjacent mainland areas and are a major concern. No studies have evaluated its potential to spread or to become established in other coastal areas in North America. Our proposed research will help fill this void. The decline of browntail moth in North America coincided with the introduction and establishment of several parasitic flies that attack browntail moth. These included browntail specialists and the generalist Compsilura concinnata that was introduced against gypsy moth. Our research will test the hypothesis that browntail moth is confined to coastal enclaves because of lower levels of parasitism by C. concinnata or lower mortality from other natural enemies.