Western University Scholarship@Western Electronic Thesis and Dissertation Repository 9-12-2018 3:00 PM Mechanisms Underlying Freeze Tolerance in the Spring Field Cricket, Gryllus veletis Jantina Toxopeus The University of Western Ontario Supervisor Sinclair, Brent J. The University of Western Ontario Graduate Program in Biology A thesis submitted in partial fulfillment of the equirr ements for the degree in Doctor of Philosophy © Jantina Toxopeus 2018 Follow this and additional works at: https://ir.lib.uwo.ca/etd Part of the Biology Commons, Cellular and Molecular Physiology Commons, Comparative and Evolutionary Physiology Commons, and the Entomology Commons Recommended Citation Toxopeus, Jantina, "Mechanisms Underlying Freeze Tolerance in the Spring Field Cricket, Gryllus veletis" (2018). Electronic Thesis and Dissertation Repository. 5708. https://ir.lib.uwo.ca/etd/5708 This Dissertation/Thesis is brought to you for free and open access by Scholarship@Western. It has been accepted for inclusion in Electronic Thesis and Dissertation Repository by an authorized administrator of Scholarship@Western. For more information, please contact
[email protected]. Abstract Freeze tolerance has evolved repeatedly across insects, facilitating survival in low temperature environments. Internal ice formation poses several challenges, but the mechanisms that mitigate these challenges in freeze-tolerant insects are not well understood. To better understand how insects survive freezing, I describe a novel laboratory model, the spring field cricket Gryllus veletis (Orthoptera: Gryllidae). Following acclimation to six weeks of decreasing temperature and photoperiod (mimicking autumn), G. veletis juveniles becomes moderately freeze-tolerant, surviving freezing at -8 °C for up to one week, and surviving temperatures as low as -12 °C.