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Joannie Tang
Environmental Science / Biology

Bill Bradshaw and Chris Holzapfel, Mentors

Genetic Correlation Between Thermal Tolerance and Critical Photoperiod in the Pitcher-Plant Mosquito, Wyeomyia Smithii

The pitcher-plant mosquito, Wyeomyia smithii, is distributed along the east coast of North America between 30 -54 N. This broad geographic range includes a large climatic gradient to which it has successfully adapted in its migration north from its ancestral origins in the tropics. I am interested in how W. smithii has been able to expand its range along a latitudinal gradient that includes environments of extreme thermal temperatures. W. smithii uses critical photoperiod (CCP), or the length of day, either to enter dormancy as days get shorter or to begin active development as days get longer. In essence, it times its development according to the season. As one progresses north, the heat of summer decreases, while the intensity of winter cold increases. Thus northern populations of W. smithii have longer critical photoperiods than southern populations. My research explores the role of CCP in the environmental range expansion of W. smithii by using two samples of a mid-latitude population, simulating in the laboratory differing weather conditions, and measuring survival rates for the samples.