title: Thermal equilibrium and temperature differences among body regions in European plethodontid salamanders.
abstract: Information on species thermal physiology is extremely important to understand species responses to environmental heterogeneity and changes. Thermography is an emerging technology that allows high resolution and accurate measurement of body temperature, but until now it has not been used to study thermal physiology of amphibians in the wild. Hydromantes terrestrial salamanders are strongly depending on ambient temperature for their activity and gas exchanges, but information on their body temperature is extremely limited. In this study we tested if Hydromantes salamanders are thermoconform, we assessed whether there are temperature differences among body regions, and evaluated the time required to reach the thermal equilibrium. During summers of 2014 and 2015 we analysed 56 salamanders (Hydromantes ambrosii and Hydromantes italicus) using infrared thermocamera. We photographed salamanders at the moment in which we found them and 1, 2, 3, 4, 5 and 15min after having kept them in the hands. Body temperature was equal to air temperature; salamanders attained the equilibrium with air temperature in about 8min, the time required to reach equilibrium was longer in individuals with large body size. We detected small temperature differences between body parts, the head being slightly warmer than the body and the tail (mean difference: 0.05°C). These salamanders quickly reach the equilibrium with the environment, thus microhabitat measurement allows obtaining accurate information on their tolerance limits.
authors: Universität Trier Fachbereich VI Raum-und Umweltwissenschaften Biogeographie, Campus I, Gebäude N Universitätsring 15, 54286 Trier, Germany; Natural Oasis, Via di Galceti 141, 59100 Prato, Italy; Museo di Storia Naturale dell'Università di Firenze, Sezione di Zoologia "La Specola", Via Romana 17, 50125 Firenze, Italy. Electronic address: enrico.arti@gmail.com.
authors: Enrico
authors: E
authors: Lunghi
authors: Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy.
authors: Raoul
authors: R
authors: Manenti
authors: Via Novara 147 P, 28047 Oleggio, Italy.
authors: Giancarlo
authors: G
authors: Canciani
authors: Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy.
authors: Giorgio
authors: G
authors: Scarì
authors: Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy.
authors: Roberta
authors: R
authors: Pennati
authors: Laboratoire d'Ecologie Alpine (LECA), Université Grenoble-Alpes, F-38000 Grenoble, France; Centre National de la Recherche Scientifique (CNRS), LECA, F-38000 Grenoble, France.
authors: Gentile Francesco
authors: GF
authors: Ficetola
mesh_terms: D000818:Animals; D049628:Body Size; D001831:Body Temperature; D013696:Temperature; D013817:Thermography; D014562:Caudata / Q000502:physiology*
keywords: Biospeleology; Head–body temperature differences; Hydromantes; Infrared termoghraphy; Speleomantes; Thermal ecology