Effects of neotyphodium endophytes on multitrophic interactions

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Melissa Elizabeth Robbins (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site: http://library.uncg.edu/
Stanley Faeth

Abstract: Endophyte-produced alkaloids may negatively affect herbivores. They may also cascade up the food web and affect the third trophic level, predators and parasites of herbivores. In this study, I examine the effect that endophyte infection and alkaloids have on two different strains of bird cherry-oat aphids (Rhopalosiphum padi) and their natural enemy, the ladybird beetle (Coleomegilla maculata). The effect of alkaloid levels produced by the endophyte-infected (E+) versus uninfected (E-) sleepygrass plants (Achnatherum robustum) was examined on aphid abundances. The effect of hybrid, non-hybrid, and uninfected Neotyphodium sp. endophytes hosted by Arizona fescue (Festuca arizonica) was examined on the abundance and feeding preference of aphids, the feeding preference of ladybird beetles, and on first and second-generation ladybird beetle development. Contrary to our expectations, aphid strains did not differ in their response to endophyte infection. However, there was a trend for lower aphid numbers on hybrid Arizona fescue and aphid preference for endophyte-free plants. Endophyte infection had large effects on second-generation ladybird beetles. Ladybird beetles on endophyte-infected plants had lower adult survival and weight than all other infection categories. My experiments demonstrate that variation in endophyte genotype and hence, alkaloids can negatively affect herbivores, but may also have negative effects on natural enemies, which may nullify their benefits to the plant.

Additional Information

Language: English
Date: 2013
Alkaloids, Coleomegilla maculata, Endophytes, Hybridization, Neotyphodium, Rhopalosiphum padi
Multitrophic interactions (Ecology)
Rhopalosiphum padi
Spotted lady beetle
Arizona fescue

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