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. 2019 Mar 12;9:4254. doi: 10.1038/s41598-019-40597-4

Figure 3.

Figure 3

Components of the novel wCTU model of development and sex determination for the TSD Painted Turtle, Chrysemys picta. (a) Developmental rate by temperature function obtained by applying the nlCTE model14 to incubation data of Painted Turtles (see text for details). OTR = Optimal Temperature Range for C. picta14. VTR = Viable Temperature Range (temperatures that induce a developmental rate > 0). Blue dots denote actual (rather than predicted) developmental rate from constant incubation experiments to illustrate de good fit of the model. (b) Cumulative Temperature Units (CTUs) sensu24 above (blue areas) and below (orange areas) the pivotal temperature (dotted line) which is 28.5 °C in C. picta used in this study. Each hourly temperature is multiplied by the developmental rate it induces (calculated from panel a to obtain the weighted CTUs (wCTUs). (c) Sex ratios of C. picta as a function of wCTUs, and fitted logistic regression (black line). Sex ratio data derive from constant and simplistic fluctuations from14,25, plus data from the novel experiments from this study. (d) Density distribution and quantile plot of temperatures from the thermal profile NatFem-ON ±6 °C that resulted in 100% mortality. The 25% to 75% quantile box depicts the average temperature (diamond) and the median temperature line. The bottom bars illustrate temperature ranges within the OTR that induce males (blue) or females (red), the ranges outside the OTR but within the VTR (gray), and the temperatures lower or higher than the most extreme values in all other profiles (black). Note that most temperatures of the NatFem-ON ±6 °C profile fell below the pivotal temperature (purple vertical line) and a substantial portion fell in the gray areas where development is retarded or in the black range of temperatures that may be lethal, perhaps explaining the high mortality of this treatment.