Скачать или смотреть Multi-isotope geolocation monitoring for an insect boreal pest - the Eastern spruce budworm

Presented by: Felipe Dargent, Ph.D, Associate Researcher, University of Ottawa



The eastern spruce budworm moth (Choristoneura fumiferana (Clem.)) is the most important pest species of the boreal forest. It has devastating outbreaks in cycles of approximately 35 years which defoliate, reduce growth and increase morality of balsam fir and spruce stands. These outbreaks in turn have severe impacts on the Canadian economy and ecological dynamics. A key driver of the extent and magnitude of outbreak impacts is the dispersal of moths from high-density (outbreak) sites to low-density (endemic) sites, which boost population growth to levels that cannot be controlled by natural enemies. Difficulty understanding dispersal comes from the fact that these are relatively rare (i.e. occur few times a year) and are directional events (i.e. the spread of moths is not isotropic on the landscape). Furthermore, traditional methods for tracking animals such as radio telemetry, mark recapture or population genetics, have limited applicability to this system. Using isotopes to track dispersal and identify the source of origin of individual migrants is a convenient and precise tool to address the above issues. Several isotopes vary spatially in a predictable manner, and are integrated into an organism’s tissues through feeding – providing a signal of where the organism grew up. We show how applying isotopic tools (in particular hydrogen δ2H, sulfur δ34S , and strontium 87Sr/86Sr) allows to distinguish between local and immigrant individuals of spruce budworm in eastern Canada, and furthermore, identify with high precision the source of origin of the immigrant individuals.