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The immune state is a key component of individuals that directly influences the physiological performance and health status, being essential for survival. Variation in the leukocyte profile, a significantly increase in body temperature, and a detriment of the eco-physiological performance are among the possible consequences of an unhealthy state. In this study we analyse and discuss how field body temperature, preferred body temperature, the speed for sprint and long runs, locomotor stamina, and body condition can be affected by the immunological state (i.e. leukocyte profile) in a wild population of Liolaemus sarmientoi. Juveniles and adult males with a high percentage of eosinophils, basophils, and a low percentage of monocytes preferred higher body temperatures in a thermal gradient, while pregnant females maintained thermal preferences independently of leukocyte profile. Although juveniles with a high percentage of heterophils showed less locomotor stamina, adult males and pregnant females showed no differences in locomotor performance in relation to leukocyte profile. This study represents a starting point in eco-immunology of a wild lizard population of Liolaemus in cold and temperate environments of Patagonia where the southward shift in the geographic ranges of pathogen populations due to global warming represents a threat to resident host populations Fil: Duran, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Boretto, Jorgelina Mariela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Fernandez, Jimena Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Ibáñez Molina, Mora. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Medina, Susana Marlin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina Fil: Ibarguengoytía, Nora. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina

In ectotherms, the likelihood of surviving an infection is determined by the efficiency of thermoregulation, the availability of a variety of thermal microenvironments, the individual's health status, and the virulence of the infective agent. Physiological and behavioral demands related to an efficient immune response entail a series of costs that compete with other vital activities, specifically energy storage, growth, reproduction, and maintenance functions. Here, we characterize the thermal biology and health status by the presence of injuries, ectoparasites, body condition, and individual immune response capacity (using phytohemagglutinin in a skin-swelling assay) of the southernmost lizards of the world, Liolaemus sarmientoi, endemic to a sub-optimal, cold environment in Patagonia, Argentina. In particular, we study the effect of a bacterial endotoxin (lipopolysaccharide; LPS-treatment) on thermoregulation. We found that the field-active body temperature (Tb) was much lower than the preferred body temperature (Tp) obtained in the laboratory. All the individuals were in good body condition at the beginning of the experiments. The phytohemagglutinin test caused detectable thickening in sole-pads at 2 h and 24 h post-assay in males and non-pregnant females, indicating a significant innate immune response. In the experimental immune challenge, the individuals tended to prefer a low body temperature after LPS-treatment (2 h post-injection) and developed hypothermia, while the control individuals injected with phosphate buffered saline (PBS), maintained their body temperature throughout the trial. In both the LPS-treatment and PBS-control individuals, BC declined during the experiment. Hypothermia may allow this southernmost species to optimize the use of their energetic resources and reduce the costs of thermoregulation in a cold-temperate environment where they rarely attain the mean Tp (35.16 °C) obtained in laboratory.

Integrative behavioral studies show that the interplay between individual physiology and social behavior influences the ecology of the species, ultimately affecting individual fitness. Particularly in lizards, color polymorphism is associated with differential behaviors and reproductive strategies, which are evident in mature males during the mating season. Dominant males generally have greater endurance, higher body temperature, and larger bodies than submissive males, so they can acquire and defend larger territories and have greater access to females for mating. We studied whether the color morphs observed in males of one of the world’s southernmost reptiles, Liolaemus sarmientoi, are related to behavioral variation during agonistic interactions, thermal physiology, morphology, and/or locomotor stamina. Liolaemus sarmientoi males exhibit three color morphs: red (RR), red–yellow (RY), and yellow (YY). These lizards exhibit subtle behavioral displays and we did not observe stamina differences among morphs. However, we found that RR males are more aggressive than YY males during agonistic encounters. In addition, greater body temperature change during trials, higher field body temperatures, and greater head sizes of RR males compared to RY or YY indicate that RR is a dominant morph, which may influence their ability to acquire and defend territory and tactics for achieving reproductive success. Fil: Fernandez, Jimena Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Bastiaans, Elizabeth. State University of New York; Estados Unidos Fil: Medina, Susana Marlin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina Fil: Méndez de la Cruz, Fausto Roberto. Universidad Nacional Autónoma de México; México Fil: Sinervo, Barry Raymond. University of California; Estados Unidos Fil: Ibarguengoytía, Nora. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina

Two hypotheses have prevailed to explain the evolution of viviparity in reptiles: the first proposed that viviparity evolved in response to cold-climates because the possibility of pregnant females to thermoregulate at higher temperatures than embryos could experience in a nest in nature. The second hypothesis posits that the advantage of viviparity is based on the possibility of females to maintain stable body temperatures during development, enhancing offspring fitness. With the aim to contribute to understanding the origins of viviparity in reptiles, we experimentally subjected pregnant females of the austral lizard Liolaemus sarmientoi to two temperature treatments until parturition: one that simulated environmental temperatures for a potential nest (17–25 °C) and another that allowed females to thermoregulate at their preferred body temperature (17–45 °C). Then, we analysed newborn body conditions and their locomotor performance to estimate their fitness. In addition, we measured the body temperature in the field and the preferred temperature in the laboratory of pregnant and non-pregnant females. Pregnant females thermoregulated to achieve higher temperatures than the environmental temperatures, and also thermoregulated within a narrower range than non-pregnant females. This could have allowed embryos to develop in higher and more stable temperatures than they would experience in a nest in nature. Thus, offspring developed at the female preferred temperature showed greater fitness and were born earlier in the season than those developed at lower environmental temperatures. Herein, we show that results are in agreement with the two hypotheses of the origin of viviparity for one of the southernmost lizards of the world. Fil: Fernandez, Jimena Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Kubisch, Erika Leticia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Ibarguengoytía, Nora. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina

Locomotor activity performance of reptiles is largely temperature dependent and, in harsh environments with short activity periods during the day and throughout the year, plays a vital role in the fitness of the species. This particular study focuses on the performance and the thermal sensitivity for running, at different body temperatures, of the two southernmost species of lizards in the world, Liolaemus sarmientoi and Liolaemus magellanicus , studied at two locations in the south of Santa Cruz province, Argentina (51°S, 70°W and 50°S, 72°W; 133 m asl). The speed of sprint and long runs was measured in the field to determine the physiological performance of lizards at different air temperatures. In both species speed increases with the temperature, and they reach the highest performance at high temperatures. The difference between activity and thermal optima suggests that L. magellanicus has colonized its actual environment recently, and that it has not had enough time for its physiological mechanisms to evolve and achieve a maximum performance at the cold temperatures they have to tolerate at present. In contrast, L. sarmientoi achieved a high performance over a wider range of temperatures that included temperatures lower than the preferred temperatures in the lab, which they can generally find in their environment.

We determined the efficiency of thermoregulation by the southernmost liolaemids Liolaemus sarmientoi and L. magellanicus from Patagonia, Argentina (51°S), by measuring body ( T b ), microenvironmental, and operative temperatures in the field, and preferred body temperatures in the laboratory ( T pref ). L. sarmientoi was found to be a poor thermoregulator, whereas L. magellanicus was deemed to be a constrained thermoconformer. Among all known species of Liolaemus , L. sarmientoi and L. magellanicus had the lowest T b' s when tested in the field; however, their T pref' s were similar to other liolaemids. These data suggest that these southernmost liolaemid species have not evolved appropriate thermoregulatory behaviors or made adequate physiological adaptations to face the extreme thermal challenges of their environment.

When an animal in the laboratory experiences a change in temperature, physiological processes are affected but they stabilize under the new temperature condition over a few weeks by a process of phenotypic plasticity called acclimation, but whether an organism can acclimate or not depends on the trait and the taxon. Liolaemus sarmientoi is one of the southernmost reptiles in the world, inhabiting the extreme and arid environment of Patagonia, Argentina, characterised by great seasonal climatic variation and cold air temperatures throughout the year (mean air temperature of 8 °C; ranging from 1.2 to 14.1 °C). However, these lizards prefer body temperatures in the laboratory ranging from 26.3 to 37.8 °C (mean Tpref = 34.4 ± 0.28 °C), temperatures that they rarely achieve in nature. Herein, we explore the effects of thermal acclimation on performance of L. sarmientoi at a temperature higher than their mean natural environmental temperature during their activity period (austral spring-summer). We analysed the speed in sprint and long runs at medium and high temperatures in the field and again after a period of acclimation of 20 days at 21 °C. Acclimation to higher and constant temperature resulted in a decrease in running speed in both long and sprint runs, suggesting potentially negative effects for natural populations if environmental temperature increases., Acta Herpetologica, Vol 7 No 2 (2012)

Liolaemus sarmientoi Donoso-Barros Liolaemus d’orbignyi Donoso-Barros & Codoceo 1962: 26; Donoso-Barros 1966a: 285. Liolaemus dorbignyi Donoso-Barros 1970a: 182 (in part); 1970b: 91 (in part). Liolaemus sarmientoi Donoso-Barros 1973b: 163 (type locality: Monte Aymond, Magallanes Region, Chile); Cei & Scolaro 1996: 391; Scolaro & Cei 1997: 376; Etheridge & Espinoza 2000: 9; Lobo 2001: 139; Chebez et al. 2005: 35; Scolaro 2005: 48; Sura 2005: 430. Liolaemus archeforus sarmientoi Cei 1975d: 113, 1986: 238; Vanzolini 1986: 16; Veloso & Navarro 1988: 500; Núñez & Jaksic 1992: 70; Etheridge 1995: 32. Liolaemus (Donosolaemus) sarmientoi Pincheira-Donoso & Núñez 2005: 66., Published as part of Pincheira-Donoso, Daniel, Scolaro, J. Alejandro & Sura, Piotr, 2008, A monographic catalogue on the systematics and phylogeny of the South American iguanian lizard family Liolaemidae (Squamata, Iguania), pp. 1-85 in Zootaxa 1800 on page 36, DOI: 10.5281/zenodo.6789337, {"references":["Donoso-Barros, R. & Codoceo, M. (1962) Reptiles de Aysen y Magallanes. Boletin del Museo Nacional de Historia Natural de Chile, 28, 1 - 45.","Donoso-Barros, R. (1966 a) Reptiles de Chile. Ediciones de la Universidad de Chile, Santiago, 458 pp.","Donoso-Barros, R. (1970 a) Liolaemus. In: Peters, J. A. & Donoso-Barros, R. (Ed.), Catalogue of the Neotropical Squamata. Part II. Lizards and Amphisbaenians. Bulletin United States National Museum, 297, 170 - 195.","Donoso-Barros, R. (1973 b) Una nueva lagartija magallanica (Reptilia, Iguanidae). Neotropica, 19, 163 - 164.","Cei, J. M. & Scolaro, J. A. (1996) A new species of Liolaemus of the archeforus group from the precordilleran valley of the Zeballos river, Santa Cruz Province, Argentina (Reptilia, Tropiduridae). Bollettino del Museo Regionale di Scienze Naturali di Torino, 14, 389 - 401.","Scolaro, J. A. & Cei, J. M. (1997) Systematic status and relationships of Liolaemus species of the archeforus and kingii groups: a morphological and taxonumerical approach (Reptilia: Tropiduridae). Bolletino Museo Regionale di Scienze Naturali di Torino, 15, 369 - 406.","Etheridge, R & Espinoza, R. E. (2000) Taxonomy of the Liolaeminae (Squamata: Iguania: Tropiduridae) and a semiannotated bibliography. Smithsonian Herpetological Information Service, 126, 1 - 64.","Lobo, F. (2001) A phylogenetic analysis of lizards of the Liolaemus chiliensis group (Iguania: Tropiduridae). Herpetological Journal, 11, 137 - 150.","Chebez, J. C., Rey, N. R. & Williams, J. D. (2005) Reptiles de los parques nacionales de la Argentina. Literatura of Latin America, Buenos Aires, 37 pp.","Scolaro, J. A. (2005) Reptiles patagonicos: Sur. Una guia de campo. Ediciones Universidad Nacional de la Patagonia San Juan Bosco, Trelew, 80 p.","Sura, P. 2005. Encyclopedia of extant amphibians and reptiles, Wydawnictwo Fundacja, Nowy Sacz, 544 pp.","Cei, J. M. (1975 d) Southern patagonian iguanid lizards of the Liolaemus kingi group. Herpetologica, 31, 109 - 116.","Cei, J. M. (1986) Reptiles del centro, centro-oeste y sur de la Argentina. Herpetofauna de las zonas aridas y semiaridas. Museo Regionale di Scienze Naturali di Torino, Monografie 4, 528 pp.","Vanzolini, P. E. (1986) Addenda and corrigenda to the Catalogue of Neotropical Squamata. Smithsonian Herpetological Information Service, 70, 1 - 25.","Veloso, A. & Navarro, J. (1988) Lista sistematica y distribucion geografica de anfibios y reptiles de Chile. Bollettino del Museo Regionale di Scienze Naturali di Torino, 6, 481 - 539.","Nunez, H. & Jaksic, F. M. (1992) Lista comentada de los reptiles terrestres de Chile continental. Boletin del Museo Nacional de Historia Natural de Chile, 43, 63 - 91.","Etheridge, R. (1995) Redescription of Ctenoblepharys adspersa Tschudi, 1845, and the taxonomy of Liolaeminae (Reptilia: Squamata: Tropiduridae). American Museum Novitates, 3142, 1 - 34.","Pincheira-Donoso, D. & Nunez, H. (2005) Las especies chilenas del genero Liolaemus (Iguania, Tropiduridae, Liolaeminae). Taxonomia, sistematica y evolucion, Publicacion Ocasional del Museo Nacional de Historia Natural de Chile, Santiago, 486 pp."]}