Lucy E Bratton, Kaitlin M Gawkins
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Insect herbivores, such as grasshoppers, are important components of grassland ecosystems, but presently we cannot accurately predict their abundance and diversity. Macronutrients (i.e., nitrogen and phosphorus) have long been considered to be important in limiting herbivore populations, but only nitrogen and phosphorus have been examined, thus overlooking a potential role for micronutrients. We are conducting a large-scale fertilization experiment manipulating micronutrients (Ca, K, and Na) and macronutrients (N and P) to determine how micronutrients affect orthopteran communities in coastal tallgrass prairies of Texas with a large, and whether the effect of micronutrients depends on the abundance of macronutrients. We found that, contrary to previous thinking, orthopterans were not limited by macronutrients, but were limited by individual micronutrients. A species of grasshopper (Melanoplus bispinosus) and multiple species of katydid (Orchelimum concinnum and Orchelimum vulgare) were particularly responsive. This summer, we will be conducting different types of feeding trials with these species to determine whether their responses are due to direct effects (i.e. via physiological mechanisms) or indirect effects (via changes in plant communities). These results would not only help to explain the mechanisms underlying of this large-scale experiment, but also, would give more insight into the relationship between direct and indirect influences of changing micronutrient concentration, thus setting a framework for further study in the future. These results have important implications for the management of rangeland ecosystems where orthopterans are highly managed pest species.
Independent Research - Undergraduate
Chelse Prather, Misty K Thomas-Trout
Primary Advisor's Department
Stander Symposium poster
"Beyond the Macro: Determining the role of micronutrients in orthopteran communities" (2017). Stander Symposium Posters. 1090.