Interactions between the forest tent caterpillar (Malacosoma disstria Hubner) and its natural enemies: the effects of forest composition and implications for outbreak spread

  • Author / Creator
    Nixon, Amy E
  • Forest tent caterpillar (Malacosoma disstria Hübner; FTC), a major defoliator of aspen trees, occupies both aspen and mixedwood forest stands in Alberta’s boreal forest. Forest stand composition could influence the spatial pattern of FTC outbreaks if mortality from natural enemies differs between stand types. I conducted field experiments to determine whether predator- or parasitoid-caused mortality of FTC differed between aspen and mixedwood forest stands and developed a spatial population model to determine the effects of variation in generalist predation on the spread of an FTC outbreak, including the effects of potential predator-caused Allee effects. Generalist predation on FTC was higher in aspen stands than in mixedwood stands, and the spatial model suggests that these observed differences may be sufficiently large to impact FTC outbreak spread rates. Forest stand composition may contribute to the spatial pattern of FTC outbreaks through variation in the impacts of predators on FTC populations.

  • Subjects / Keywords
  • Graduation date
    Fall 2011
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.