Examining the role of macrogeographic variables in predicting key phenotypes in a widespread reptile lessons from the lab and field


Meeting Abstract

11-5  Thursday, Jan. 4 09:00 – 09:15  Examining the role of macrogeographic variables in predicting key phenotypes in a widespread reptile: lessons from the lab and field BODENSTEINER, B/L*; WARNER, D/A; IVERSON, J/B; MILNE-ZELMAN, C/L; MITCHELL, T/S; REFSNIDER, J/M; VOVES, K/C; JANZEN, F/J; Virginia Tech; Auburn University; Earlham College; Aurora University; Auburn University; University of Toledo; Iowa State University; Iowa State University bodenbro@vt.edu

Species with large geographic ranges experience considerable variation in climate, and are thus key reservoirs of ecological, phenotypic, and genetic diversity. Such organisms are excellent systems for revealing the process of local adaptation and divergence. Maternal effects, such as nest-site choice, may impact offspring phenotypes and survival, and thus have the potential to mitigate the effects of divergent climatic conditions. Understanding how variation in key traits are spatiotemporally distributed across species’ ranges will improve our predictions of current and future adaptation to climate change. We examined natural nesting areas in six populations of painted turtles (Chrysemys picta), spanning ~15° latitude, and quantified spatial and temporal variation in nest microhabitat characteristics across the nesting season. At all sites females nested non-randomly, selecting nest sites with a warmer nesting environment when compared to the area available for nesting in a given location. Natural nest microhabitats differed among locations, but did not predictably vary with latitude during development for a given location. The distribution of our thermal data suggests that females choose nest sites that buffer against developmental minimum temperatures, rather than maximum environmental temperatures. Thus, nest-site choice may be unlikely to compensate for the novel stressor of rapidly increasing ambient temperatures in these populations. Elucidating how organisms with temperature-sensitive traits persist in these vastly different environments is key to predicting how they may respond to rapidly changing thermal conditions predicted under climate change models.

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