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Harvard Forest Research Project 2023

  • Title: Monitoring the spread of the invasive winter moth and the formation of a stable hybrid zone with the native Bruce spanworm
  • Principal investigator: Jeremy Andersen (jcandersen@umass.edu)
  • Institution: University of Massachusetts - Amherst
  • Primary contact: Jeremy Andersen (jcandersen@umass.edu)
  • Team members: Joseph Elkinton
    David Orwig
  • Abstract:

    Winter moth is a non-native invasive defoliator that has caused widespread tree damage and mortality in eastern Massachusetts. Since its introduction to eastern North America in the late 1990s, winter moth has spread westward into the interior of Massachusetts, and now can be found frequently in locations from Fitchburg to the coast. Curiously, the rate of spread of winter moth has declined since its introduction. We believe that this decrease is due to a combination of factors, 1) that a stable hybrid zone has formed where winter moth comes into contact with the native Bruce spanworm, and 2) that decreasing winter temperatures further from the coast cause mortality to the adults (unlike most insects winter moths are active during the winter months) or prevent males from flying to find mates (due to energetic constraints associated with exothermic organisms). To better understand these two factors, we have established a transect along Route 2 in Massachusetts that has been sampled yearly since 2007. In 2018, we started sampling the transect either weekly or bi-weekly to capture differences in the timing of flight of winter moth and Bruce spanworm. In 2022, we further expanded our sampling to include locations in western and central Massachusetts (including Amherst), and were surprised to find winter moth present in these locations. This might be a result of warmer soil temperatures and/or other urban heat effects. Therefore, we propose to survey a mixed-oak stand at Harvard Forest with the hopes that we can 1) better understand the geographic distribution of winter moth, and 2) compare soil temperature data to emergence timing.