Meeting Abstract

84.4  Sunday, Jan. 6  Evolution on Your Porch: Physiological Adaptation by Mediterranean House Geckos to their Introduced Niches DICKSON, M.M.*; ZIMMERMANN, S.A.; LIWANAG, H.E.M.; ESPINOZA, R.E.; California State University, Northridge; California State University, Northridge; California State University, Northridge; Adelphi University; California State University, Northridge matthew.dickson.417@my.csun.edu

Adaptation is essential for organisms to persist in changing environments. Physiological adaptations should be especially important to ectotherms, which are closely coupled to their abiotic environments. Introduced species may be more likely to evolutionarily adapt to local climates because of small founder populations and strong selective pressures in their new environments. To test these ideas, we compared the thermal tolerances (critical thermal minimum, CT_min and panting threshold, T_pant) and temperature-dependent rates of evaporative water loss (EWL) of Mediterranean House Geckos (Hemidactylus turcicus) from different climates. These familiar “porch light” geckos have been widely introduced throughout North America over the past century. Introduced geckos were collected from regions representing three climates: desert (hot/dry), Mediterranean (warm/dry), and semitropical (hot/humid). We hypothesized that geckos from these three climates would exhibit differences in temperature tolerances and EWL consistent with local adaptation. Geckos experiencing lower daytime temperatures had lower CT_min compared to geckos from hotter climates, consistent with local adaptation. However, we found no significant differences in T_pant among geckos from differing climates. Geckos from arid climates had lower rates of EWL at high temperatures compared to geckos from humid regions, also indicating adaptive evolution. Future studies will include temperature-dependent metabolism and sprint performance. Ultimately these data will be used to develop mechanistic climatic niche models to predict the future range expansion of this species in North America.