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Full-Text Articles in Ecology and Evolutionary Biology
Regional Comparison Of Overwintering Mortality, Fecundity, And Virulence In The Hemlock Woolly Adelgid, Artemis Demas Roehrig
Regional Comparison Of Overwintering Mortality, Fecundity, And Virulence In The Hemlock Woolly Adelgid, Artemis Demas Roehrig
Masters Theses 1911 - February 2014
Throughout the eastern United States, the spread of the hemlock woolly adelgid, Adelges tsugae Annand, has caused high mortality of eastern hemlocks Tsuga canadensis (L.). We recorded overwintering survival and fecundity of A. tsugae, and tree new growth at sites in the northeastern and southeastern United States and in a common garden experiment in Massachusetts.
Overwintering mortality of A. tsugae was much higher in the north (87%) than the south (37%) in 2009, and showed significantly positive density-dependence in the north only. In 2010, overwintering mortality decreased in both regions but remained higher in the north (54%) than the …
Resin Volatiles Of Eastern Hemlock Induced By Its Non-Native Herbivores, Joshua D. Pezet
Resin Volatiles Of Eastern Hemlock Induced By Its Non-Native Herbivores, Joshua D. Pezet
Masters Theses 1911 - February 2014
Eastern hemlock (Tsuga canadensis) is in decline because of infestation by the invasive hemlock woolly adelgid (Adelges tsugae; ‘HWA’) and, to a lesser extent, the elongate hemlock scale (Fiorinia externa; ‘EHS’). Many conifers respond to insect herbivory by inducing oleoresin-based defenses, however it is unknown whether eastern hemlock is capable of this inducible response. We conducted a plantation setting study of artificially infested saplings to determine if feeding by HWA or EHS induces changes in the tree’s volatile chemistry. The induced changes in volatiles we found were unlike the terpenoid-based defenses of related conifers. Only HWA feeding …