Geographic variation in thermal sensitivity of early life-history traits in a widespread reptile


Meeting Abstract

114-7  Thursday, Jan. 7 11:45  Geographic variation in thermal sensitivity of early life-history traits in a widespread reptile BODENSTEINER, B.L.*; WARNER, D.A.; IVERSON, J.B.; MILNE-ZELMAN, C.; MITCHELL, T.S.; REFSNIDER, J.M.; JANZEN, F.J; Iowa State University; Auburn University; Earlham College; Aurora University; Auburn University; The University of Toledo; Iowa State University bodenbro@iastate.edu

Organisms with large geographic distributions may experience a great diversity of climatic conditions. Therefore many of these organisms must locally adapt or exhibit phenotypic plasticity. These processes are of particular interest in organisms with traits that are intrinsically connected to temperature, including embryonic development. To examine potentially adaptive spatial patterns in a widespread vertebrate, we quantified early life-history traits of the painted turtle (Chrysemys picta) from seven distinct populations across its geographic range (Kansas, Illinois, New Mexico, Oregon, Minnesota, Idaho, and Nebraska). Eggs from these populations were incubated under constant conditions across a range of environmentally relevant temperatures. We measured incubation duration, hatchling body size and condition, and morphological abnormalities to quantify differences in phenotypic reaction norms across these populations. We hypothesized that incubation duration at a given temperature would vary among populations. Secondly, we predicted that northern populations would be more sensitive to thermal variation due to shorter seasons and more variable temperatures in nature. Better understanding spatial variation in key traits of these organisms will provide insights into current adaptations to local climatic variation and potentially into future phenotypic responses to projected global climate change.

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