Date of Award


Degree Type


Degree Name

Master of Science




Dr. Brent Sinclair

Second Advisor

Dr. Chris Guglielmo

Third Advisor

Dr. Sheila Macfie


Insects survive subzero environments by using cold tolerance strategies divided into two categories: freeze avoidance or freeze tolerance. In spite of extensive research on insect cold tolerance, it remains unclear whether a phylogenetic constraint exists on the “choice” of cold tolerance strategy. Most freeze tolerant dipteran species survive freezing as larvae; however, previous Drosophila studies have focused primarily on the adult fly. I suggest that both freeze avoiding and freeze tolerant strategies will be present in Drosophila larvae, and I used a comparative approach to examine this and other cold tolerance attributes in a phylogenetically-independent context. Supercooling capacity was attributed primarily to physical factors, while the relationship between basal and inducible cold tolerance was due to evolutionary relatedness. Freeze tolerance was not observed; however, freeze avoiding species were distinct from chill susceptible species, which appeared to be basal within the genus. Freeze avoiding strategies have arisen multiple times in Drosophila.



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