Invertebrate Diversity on Sleepy Grass (Achnatherum Robustum) Infected with the Alkaloid-Producing Neothyphodium Fungal Endophyte
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Authors
Faust, Mara K.
Issue Date
2004
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
Sleepy grass (Achnatherum robustum) is a cool-season native grass of the
southwestern United States that is inhabited by a fungal endophyte of the genus
Neotyphodium. The relationship between Neotyphodium and host grasses is thought to be mutualistic. The endophyte produces several types of alkaloids that are known to cause toxicosis in vertebrate herbivores such as cattle. In fact, plants infected with the
endophyte are avoided by some vertebrate herbivores. In this investigation, it was
hypothesized that the alkaloid levels produced by a plant's endophytic fungi result in a
change in community composition on the plant. To test this hypothesis, a vortex sampler
was used to collect invertebrates from individual sleepy grass plants at three sites in
southern New Mexico. The invertebrates were sorted into morphospecies, which were
used to calculate a diversity index for each individual plant. Alkaloid concentrations in
plant tissues were determined using high-pressure liquid chromatography. Invertebrate
abundance, species richness and diversity were correlated with plant size and the alkaloid levels produced by each plant. Plant volume significantly affected abundance, species richness, and diversity of invertebrates. Alkaloid concentration in plant tissues was positively related to species richness. These results question the hypothesis that alkaloids associated with endophytes reduced abundance and diversity of invertebrate communities on host grasses.
Description
vi, 26 p.
Citation
Publisher
Kalamazoo College
License
U.S. copyright laws protect this material. Commercial use or distribution of this material is not permitted without prior written permission of the copyright holder.