Department Chair

Daniel L. Potts, Ph.D., Chair and Associate Professor of Biology

Date of Award


Access Control

Open Access

Degree Name

Biology, M.A.


Biology Department


Robert J. Warren II, Ph.D., Associate Professor of Biology

Department Home page

First Reader

Christopher Pennuto, Ph.D., Professor of Biology

Second Reader

Olga Novikova, Ph.D., Assistant Professor of Biology


Organisms produce weapons for defense against pathogens and competitors. In response, competitors and pathogens develop resistance to these weapons. However, when a species invades a new range, its “novel weapons” may be more effective against native species that did not co-evolve with them. Via specialized glands and microbial associates, ants produce antifungal weapons for defense against entomopathogenic fungi. However, these weapons may have unintended secondary effects on non-entomopathogenic, soil and seed-borne fungi. The antifungals of non-native ants may be novel weapons, with greater negative impacts on native fungi that have not co-evolved with them. This research aims to test the novel weapons hypothesis by comparing the impacts of an invasive European ant, Myrmica rubra, against those of a native North American ant, Aphaenogaster picea, on a native North American fungus, Absidia sp. I hypothesized that M. rubra would reduce fungal performance as compared to A. picea. To test this hypothesis, I isolated Absidia sp. from ant-occupied soils, exposed cultures to ant colonies, and measured the percent cover of Absidia sp. after 48 hours. Percent cover of Absidia sp. was lowest in M. rubra, greater in A. picea, and greatest with no ants. Percent cover of ant-facilitated microbes was greatest in M. rubra, lower in A. picea, and lowest with no ants. Ant-facilitated microbe cover correlated negatively with Absidia sp., but, under high resource conditions, Absidia sp. negatively impacted ant-facilitated microbes. Both ant species reduced Absidia sp. cover. However, M. rubra exerted stronger negative effects, consistent with the novel weapons hypothesis.

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