Date of Award

8-2008

Level of Access Assigned by Author

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Ecology and Environmental Sciences

Advisor

Eleanor Groden

Second Committee Member

Francis A. Drummond

Third Committee Member

Andrei Alyokhin

Abstract

Invasive ants have detrimentally altered native habitats, with effects felt on plants and other arthropod taxa. The European fire ant, Myrmica rubra (Linnaeus), is an invasive ant in over 42 communities in Maine. I used insect survey techniques (sweepnet, visual, terminal branch sampling, and comparative plant surveys) and field experiments to test the effects of M. rubra on homopteran abundance in the summers of 2006 and 2007 on Mount Desert Island, ME. Two out of three sampling techniques detected significantly higher abundances of the aphids, Aphis spiraephila Patch and Prociphilus tessellatus Fitch, as well as species of Diaspididae, Coccidae, and Cicadellidae. An ant exclusion field experiment on the native plant meadowsweet, Spiraea alba Du Roi, found higher abundances of A. spiraephila with M. rubra tending compared with native ant tending. A predator exclusion field experiment was conducted on S. alba using adult ladybeetles, Hippodamia convergens Guérin-Méneville, larval lacewings, Chyrsoperla carnea Stephens, and no predators. In the presence of M. rubra, aphid populations were negatively impacted but at a much reduced rate in C. carnea treatments and only marginally with H. convergens. Fifty-two behavioral assays were carried out to test the responses of H. convergens adults and M. rubra tending hompoterans. H. convergens were readily attacked and responded with escape behaviors. Myrmica rubra may be increasing particular species of Homoptera instead of all species of Homoptera in infested sites.

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