title: Would behavioral thermoregulation enable pregnant viviparous tropical lizards to cope with a warmer world?
abstract: Sceloporus lizards depend on external heat to achieve their preferred temperature (Tsel) for performing physiological processes. Evidence both in the field and laboratory indicates that pregnant females of this Genus select body temperatures (Tb) lower than 34 °C as higher temperatures may be lethal to embryos. Therefore, thermoregulation is crucial for successful embryo development. Given the increase in global air temperature, it is expected that the first compensatory response of species that inhabit tropical climates will be behavioral thermoregulation. We tested whether viviparous Sceloporus formosus group lizards in the wild exhibited differences in thermoregulatory behavior to achieve the known Tselfor developing embryos regardless of local thermal conditions. We quantified field active body temperature, thermoregulatory behavior mechanisms (time of sighting, microhabitat used and basking time) and available microhabitat thermal conditions (i.e. operative temperature) for 10 lizard species during gestation, distributed along an altitudinal gradient. We applied both conventional and phylogenic analyses to explore whether Tbor behavioral thermoregulation could be regulated in response to different thermal conditions. These species showed no significant differences in field Tbduring gestation regardless of local thermal conditions. In contrast, they exhibited significant differences in their behavioral thermoregulation associated with local environmental conditions. Based on these observations, the differences in thermoregulatory behavior identified are interpreted as compensatory adjustments to local thermal conditions. We conclude that these species may deal with higher temperatures predicted for the tropics by modulating their thermoregulatory behavior.
authors.affiliation: Departament of Zoology, Institute of Biology, National Autonomous University of Mexico, Mexico City, Mexico.
authors.forename: Saúl
authors.initials: S
authors.lastname: López-Alcaide
authors.affiliation: Center for Research in Mathematics, Guanajuato, Mexico.
authors.forename: Miguel
authors.initials: M
authors.lastname: Nakamura
authors.affiliation: Amphibian and Reptile Diversity Research Center and Department of Biology, University of Texas at Arlington, Arlington, Texas, USA.
authors.forename: Eric N
authors.initials: EN
authors.lastname: Smith
authors.affiliation: Departament of Zoology, Institute of Biology, National Autonomous University of Mexico, Mexico City, Mexico.
authors.forename: Enrique
authors.initials: E
authors.lastname: Martínez-Meyer
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D001833:Body Temperature Regulation; D005260:Female; D008116:Lizards; D013696:Temperature
keywords: Sceloporus formosus; altitudinal gradient; behavior; global warming; thermal stress