Temperature- Dependent Sex Determination (TSD) of Painted Turtles, Chrysemys picta


The project that I have been undertaking during the spring 2014 semester is based on Professor Scott Boback’s research on Painted turtle nesting at a man-made pond located in Cumberland County, Pennsylvania. The specific study site is located at the Hunstsdale Fish Hatchery in Huntsdale, Pennsylvania. The sex of an embryo is temperature-dependent and has a spatially relevant factor as to where nests are located. Nest sites and attempted sites are constrained between a railroad and pond, creating a highly spatially restricted data sample. The data will be geographically and temporally organized and then displayed in relation to temperature readings from a recording device (ibuttons, Embedded Data Systems). There was a set of sixteen active nest sites, which could be correlated to ibutton data based on date and time. Furthermore, an Inverse Weighting Distribution was used within a minimum-bounding rectangle to better interpret the variation in temperature spatially and temporally.

Within my poster, I have displayed the use of Inverse Distance Weighting (IDW) for individual dates to model temperature fluctuations, spatially, within the study site. The July dates were chosen based on any extreme temperature fluctuations during the month of July 2011 that corresponded with extreme displays of temperature depicted by the model among the study site nests. This research is important at a greater scale as this species, along with other temperature-dependent sex determinate species, are very sensitive to overall global temperature changes. If temperature were to rise even by a few degrees, that shift in climate could produce all female offspring clutches and the eventual extinction of the species.