Meeting Abstract
The transformation of natural habitat worldwide into urban landscape dramatically alters thermal environments, which can impact local biota. Urban areas often provide novel environments that exhibit greater temperature variation than natural areas (e.g., urban heat island effect). Ectothermic organisms that are oviparous are particularly sensitive to these altered environments because their embryos cannot behaviorally thermoregulate and the surrounding environment determines the temperature experienced during development. In this study, we evaluated the effects of incubation temperatures on development and hatchling phenotypes of two non-native lizards (Anolis sagrei and Anolis cristatellus) from two metropolitan areas of Miami, Florida. To determine if embryos from urban and natural habitats are adapted to their respective thermal environments, we incubated eggs from each habitat using temperatures that simulate likely nest conditions in both urban and natural sites. For both species, urban thermal environments accelerated embryonic development, but had no impact on egg survival or any of the phenotypic traits that were measured (e.g., body size, running performance, and locomotor behavior). Our results provide no evidence that embryos from urban and natural habitats are adapted to their respective thermal environments. Instead, the lack of any major effects suggest that embryos of both species are physiologically robust with respect to novel environments, which could have facilitated their success in establishing in non-native ranges and in human-modified habitats. Future studies on the growth and survival of these hatchlings in the field will help shed light on when adaptation and acclimation might occur.
