Defense Date


Document Type


Degree Name

Master of Science



First Advisor

Dr. Karen M. Kester

Second Advisor

Dr. Salvatore J. Agosta


Among the predicted impacts associated with global climate change, warming is of special interest because the rates of physiological processes are temperature-dependent. Insects and other ectotherms are likely to be affected due to their limited ability to control body temperature. In this study, I measured the tolerance to extreme high temperatures, i.e., critical thermal maximum (CTmax), of component species in a tri-trophic system, including an herbivore (Manduca sexta), a primary larval parasitoid (Cotesia congregata) and a hyperparasitoid (genus Silochalcis). For wild insects, the parasitoid had the lowest CTmax, the hyperparasitoid had the highest, and the herbivore was intermediate. For laboratory insects, the parasitoid had a lower CTmax than the herbivore. Results suggest that laboratory colonies can be used to predict relative thermal performance of interacting species in the field. Variations in tolerance to high temperature among component species could disrupt the outcome of interactions in multi-trophic systems.


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Available for download on Monday, August 09, 2021