Influence of endophytic fungi infecting tall fescue on parasitoid performance
Dr. Thomas Bultman, Hope College
Neotyphodium coenophialum (Ascomycota: Clavicipitaceae) is an endophytic fungus that lives symbiotically within the stems, leaf sheaths, and seeds of its host grass, tall fescue (Lolium arundinaceum) and produces toxic alkaloids that are deterrents to herbivores by negatively impacting growth, development, and survival. These negative impacts may be carried over to natural predators of the herbivores. In this study, my objective was to examine if Neotyphodium in the diet of aphids, Rhopalosiphium padi, affect the performance of their parasitoid, Aphidius matricariae, by means of survival rate, developmental time, body mass, and size. Aphids were fed either tall fescue infected with or lacking the endophyte and then parasitoids were allowed to parasitize the aphids. Although not statistically significant and contrary to predictions, parasitoids reared on aphids fed infected tall fescue actually tended to have greater survival rates, shorter developmental times, and greater mass and tibia lengths then their E- treatment counterparts. The results suggest that consumption of endophytic grass may not have a negative impact on parasitoid performance.
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