DOI
https://doi.org/10.25772/80FW-8Y24
Defense Date
2020
Document Type
Thesis
Degree Name
Master of Science
Department
Biology
First Advisor
Dr. Karen Kester
Second Advisor
Dr. Salvatore Agosta
Third Advisor
Dr. Shelley Adamo
Fourth Advisor
Dr. Derek Johnson
Fifth Advisor
Dr. D'Arcy Mays
Abstract
Insect thermoregulatory research has demonstrated evidence of variation occurring within and among species with respect to infection, pathogens, and parasitism, but few studies have examined differences in thermoregulatory behavior in a host-parasite system with a coevolved symbiotic virus. I investigated the role of parasitism by Cotesia congregata (Say) (Hymenoptera: Braconidae) on the thermoregulatory behavior of Manduca sexta (L.) (Lepidoptera: Sphingidae) using an experimental design in a thermal gradient chamber and a complementary observational field study on wild M. sexta collected from tobacco farms. Parasitism and larval age were not found to have a significant effect on the preferred body temperature of M. sexta caterpillars. However, an interaction between parasitization status and larval age resulted in significant differences in the change in body temperature from the beginning to the end of the experiment. I believe this can be explained by both parasitized and unparasitized caterpillars at later instar stages having a greater temperature lag (surface temperature - body temperature). Results indicate the combined effect of parasitism by C. congregata and infection with a coevolved symbiotic virus does not induce behavioral fever in M. sexta. While thermoregulation did not differ between parasitized and unparasitized caterpillars in the thermal gradient chamber, caterpillars with post-emergent wasp larvae were found significantly higher on plants at collection sites than unparasitized caterpillars. In light of the field results, I recommend that a standardized thermal gradient chamber with an additional vertical axis be used in future studies of lepidopteran thermoregulation.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
5-22-2020
Included in
Behavior and Ethology Commons, Biology Commons, Entomology Commons, Other Ecology and Evolutionary Biology Commons, Parasitology Commons