Abstract Detail

Ecology

Pittenger, Madison [1], Caudle, Keri [2], Baer, Sara [3], Johnson, Loretta [4], Maricle, Brian [5].

Herbivory preferences among ecotypes of big bluestem (Andropogon gerardii).

Big bluestem (Andropogon gerardii), a dominant prairie grass, exhibits a wide distribution with numerous genetically distinct ecotypes. Despite being within the same species, each ecotype uniquely adapts to abiotic and biotic factors within its own environment. These adaptations may prove more or less desirable to herbivores in the area. For instance, plants adapted to areas with greater rainfall tend to grow larger than those adapted to drier conditions. However, wetter conditions might result in greater numbers of herbivores, so ecotypes adapted to wetter conditions might have evolved greater herbivore defense mechanisms. We hypothesized that herbivores would display a preference for plants adapted to drier conditions. We tested this with feeding preference trials involving grasshoppers and leaves from five ecotypes of A. gerardii that represented plants adapted to wet and dry conditions. Scans of leaves before and after herbivory trials indicated the percentage of the leaf eaten. We also hypothesized that leaves with more mechanical tissue would be less preferable to herbivores. Physical strength of leaves was measured by mechanical measures of ripping and tearing. Following herbivory trials, 45 to 59 percent of leaf area remained, but no significant differences were detected among ecotypes regarding herbivory preference or physical strength measures. This likely resulted from duration of herbivore treatments; shorter treatments may have captured a true preference as opposed to leaf availability. However, these data also suggest that ecotypes of A. gerardii have evolved similar tolerances to herbivory. Perhaps different environmental factors are stronger selective pressures than herbivory.

1 - Fort Hays State University, Department of Biological Sciences, 600 Park St., Hays, KS, 67601, USA
2 - Fort Hays State University, Department of Biological Sciences, 600 Park St., Hays, KS, 67601, United States
3 - Southern Illinois University, Plant Biology and Center for Ecology, Carbondale, IL, 62901, USA
4 - Kansas State University, Biology, Ackert Hall Rm 232, Manhattan, KS, 66506-4901, USA
5 - Fort Hays State University, Department Of Biological Sciences, 600 Park St., Hays, KS, 67601-4099, USA

Keywords:
population
herbivore
ecotype
big bluestem.

Presentation Type: Poster
Session: P, Ecology Section Posters
Location: Exhibit Hall/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 5:30 PM This poster will be presented at 5:30 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PEC007
Abstract ID:171
Candidate for Awards:Ecological Section Best Undergraduate Presentation Award