Monitoring Population Levels of Two Purple Loosestrife-Eating Beetles, Galerucella calmariensis and G. pusilla, at Pointe Mouille State Game Area
Boylan, Colleen F.
MetadataShow full item record
Purple loosestrife's aggressive and invasive qualities are having drastic negative effects on the wetlands of North America. Although purple loosestrife began colonizing North America in the early 1800's, attempts at biological control were not initiated until the 1990's. After forty years of traditional control, measures were found to stem the flood of purple loosestrife across the continent. Biological control tests located two highly host specific species of beetles found to control purple loosestrife in its native Northern Germany habitat. The population levels of Galerucella pusilla and G. calmariensis at Pointe Mouillee State Game Area were monitored using weekly beetle counts from three different locations. The locations differed in their water levels, time of release and number of beetles released, and environment. The driest location, the Walpatich Unit, had an exceptional success rate for the beetles. Two generations of new adults hatched during one summer, a rarity in its native habitat. Data demonstrated that habitat is a large corollary in the survival and reproductive rates of the Galerucella. Vegetation maps were prepared to provide valuable predictors of how the areas will appear in the future. Although biological control began at the end of the twentieth century, the effects will not become apparent until ten or fifteen years later.