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López-Reyes K, Yáñez-Arenas C, Villalobos F. Exploring the causes underlying the latitudinal variation in range sizes: Evidence for Rapoport's rule in spiny lizards (genus Sceloporus). PLoS One 2024; 19:e0306832. [PMID: 38980894 PMCID: PMC11233011 DOI: 10.1371/journal.pone.0306832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 06/24/2024] [Indexed: 07/11/2024] Open
Abstract
Species' range size is a fundamental unit of analysis in biodiversity research, given its association with extinction risk and species richness. One of its most notable patterns is its positive relationship with latitude, which has been considered an ecogeographical rule called Rapoport's rule. Despite this rule being confirmed for various taxonomic groups, its validity has been widely discussed and several taxa still lack a formal assessment. Different hypotheses have been proposed to explain their potential mechanisms, with those related to temperature and elevational being the most supported thus far. In this study, we employed two level of analyses (cross-species and assemblage) to investigate the validity of Rapoport's rule in spiny lizards (genus Sceloporus). Additionally, we evaluated four environmental-related hypotheses (minimum temperature, temperature variability, temperature stability since the last glacial maximum, and elevation) posed to explain such pattern, contrasting our results to those patterns expected under a null model of range position. Our results provided support for Rapoport's rule at both levels of analyses, contrasting with null expectations. Consistently, minimum temperature and elevation were the most relevant variables explaining the spatial variation in range size. At the cross-species level, our null simulations revealed that both variables deviated significantly from random expectations. Conversely, at the assemblage level, none of the variables were statistically different from the expected relationships. We discussed the implication of our findings in relation to the ecology and evolution of spiny lizards.
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Affiliation(s)
- Kevin López-Reyes
- Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México (UNAM), Mérida, México
- Laboratorio de Ecología Geográfica, Unidad Académica Sisal, Facultad de Ciencias, Unidad de Conservación de la Biodiversidad, Parque Científico y Tecnológico de Yucatán, Universidad Nacional Autónoma de México, Mérida, Yucatán, México
- Laboratorio de Macroecología Evolutiva, Red de Biología Evolutiva, Instituto de Ecología A.C.-INECOL, Xalapa, Veracruz, México
| | - Carlos Yáñez-Arenas
- Laboratorio de Ecología Geográfica, Unidad Académica Sisal, Facultad de Ciencias, Unidad de Conservación de la Biodiversidad, Parque Científico y Tecnológico de Yucatán, Universidad Nacional Autónoma de México, Mérida, Yucatán, México
| | - Fabricio Villalobos
- Laboratorio de Macroecología Evolutiva, Red de Biología Evolutiva, Instituto de Ecología A.C.-INECOL, Xalapa, Veracruz, México
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2
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Horváth G, Sos T, Bóné G, Lőrincz CE, Pap PL, Herczeg G. Integrating behavioural thermoregulatory strategy into the animal personality framework using the common lizard, Zootoca vivipara as a model. Sci Rep 2024; 14:14200. [PMID: 38902323 PMCID: PMC11189939 DOI: 10.1038/s41598-024-64305-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 06/07/2024] [Indexed: 06/22/2024] Open
Abstract
The study of consistent between-individual behavioural variation in single (animal personality) and across two or more behavioural traits (behavioural syndrome) is a central topic of behavioural ecology. Besides behavioural type (individual mean behaviour), behavioural predictability (environment-independent within-individual behavioural variation) is now also seen as an important component of individual behavioural strategy. Research focus is still on the 'Big Five' traits (activity, exploration, risk-taking, sociability and aggression), but another prime candidate to integrate to the personality framework is behavioural thermoregulation in small-bodied poikilotherms. Here, we found animal personality in thermoregulatory strategy (selected body temperature, voluntary thermal maximum, setpoint range) and 'classic' behavioural traits (activity, sheltering, risk-taking) in common lizards (Zootoca vivipara). Individual state did not explain the between-individual variation. There was a positive behavioural type-behavioural predictability correlation in selected body temperature. Besides an activity-risk-taking syndrome, we also found a risk-taking-selected body temperature syndrome. Our results suggest that animal personality and behavioural syndrome are present in common lizards, both including thermoregulatory and 'classic' behavioural traits, and selecting high body temperature with high predictability is part of the risk-prone behavioural strategy. We propose that thermoregulatory behaviour should be considered with equal weight to the 'classic' traits in animal personality studies of poikilotherms employing active behavioural thermoregulation.
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Affiliation(s)
- Gergely Horváth
- Department of Systematic Zoology and Ecology, Institute of Biology, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/c, 1117, Budapest, Hungary.
- HUN-REN-ELTE-MTM Integrative Ecology Research Group, Pázmány Péter sétány 1/C, 1117, Budapest, Hungary.
| | - Tibor Sos
- Evolutionary Ecology Group, Hungarian Department of Biology and Ecology, Centre for Systems Biology, Biodiversity and Bioresources, Babeş-Bolyai University, Clinicilor street 5-7, Cluj-Napoca, Romania
- "Milvus Group" Bird and Nature Protection Association, B-dul 1 Decembrie 1918 121, 540445, Tîrgu Mureș, Romania
| | - Gábor Bóné
- "Milvus Group" Bird and Nature Protection Association, B-dul 1 Decembrie 1918 121, 540445, Tîrgu Mureș, Romania
| | - Csanád Endre Lőrincz
- Department of Physiology, Anatomy and Neuroscience, Faculty of Science and Informatics, University of Szeged, Közép fasor 52, 6726, Szeged, Hungary
| | - Péter László Pap
- Evolutionary Ecology Group, Hungarian Department of Biology and Ecology, Centre for Systems Biology, Biodiversity and Bioresources, Babeş-Bolyai University, Clinicilor street 5-7, Cluj-Napoca, Romania
| | - Gábor Herczeg
- Department of Systematic Zoology and Ecology, Institute of Biology, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/c, 1117, Budapest, Hungary
- HUN-REN-ELTE-MTM Integrative Ecology Research Group, Pázmány Péter sétány 1/C, 1117, Budapest, Hungary
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3
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Thermal ecophysiology of Basiliscus galeritus (Squamata: Corytophanidae) in two populations at different altitudes: Does the crest participate actively in thermoregulation? J Therm Biol 2021; 99:102980. [PMID: 34420624 DOI: 10.1016/j.jtherbio.2021.102980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 11/22/2022]
Abstract
Thermoregulation is a critical process for ectotherms as non-avian reptiles, since their vital physiological processes depend on it. These organisms have a temperature range where their physiological processes are more efficient, this range is usually a requirement set phylogenetically even though they vary in the use of habitats. This research compares the thermal ecophysiology of Basiliscus galeritus (western basilisk) in two populations with altitudinal differences in the northwestern of Ecuador. The results suggest that the difference of altitude between the two locations (500 m) influences the thermal ecophysiology of the species since the body temperature (Tb), operative temperature (Te) and preferred body temperature (Tset) showed significative differences. Furthermore, B. galeritus obtains its Tb through heliothermy and it behaves as an active thermoregulator. On the other hand, the crest temperatures reach higher values than their Tset, the results suggested that the species uses the crest as an alternative to regulate its body temperature when exceeding its Tset. Besides, this thermoregulatory behavior has been suggested only in some extinct synapsids.
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4
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Fernández-Rodríguez I, Barroso FM, Carretero MA. An integrative analysis of the short-term effects of tail autotomy on thermoregulation and dehydration rates in wall lizards. J Therm Biol 2021; 99:102976. [PMID: 34420620 DOI: 10.1016/j.jtherbio.2021.102976] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/13/2021] [Accepted: 04/18/2021] [Indexed: 11/26/2022]
Abstract
Maintaining body temperature is essential for the optimal performance of physiological functions. Ectotherms depend on external heat sources to thermoregulate. However, thermoregulation may be constrained by body condition and hydration state. Autotomy (i.e., the voluntary shed of a body part) evolved in various animal lineages and allowed surviving certain events (such as predator attacks), but it may affect body condition and volume/surface ratios, increase dehydration and constrain thermoregulation. In the framework of a general analysis of the evolution of autotomy, here we assessed the effects of tail loss on the thermal preferences and evaporative water loss rates (EWL) in the lizard Podarcis bocagei, integrating the thermal and hydric factors. We did not observe shifts in the thermal preferences of experimentally autotomized lizards when compared to the controls, which contradicted the hypothesis that they would raise preferred temperature to increase metabolic rates and accelerate regeneration. Evaporative water loss rates were also similar for tailed and tailless individuals, suggesting negligible increase of water loss through the injury and no specific ecophysiological responses after autotomy. Therefore, the changes observed in autotomized lizards in the field are to be considered primarily behavioural, rather than physiological, and thermoregulation could be secondarily affected by behavioural compensations for an increased predation risk after autotomy. Functional studies are necessary to understand how lizards' interaction with the environment is altered after autotomy, and further studies including different dehydration levels would be useful to fully understand the effect of water shortage on lizards' performance after caudal autotomy.
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Affiliation(s)
- Irene Fernández-Rodríguez
- CIBIO, Research Centre in Biodiversity and Genetic Resources, InBIO, Universidade do Porto, Campus de Vairão, Rua Padre Armando Quintas, nº7, Vairão, 4485-661, Vila do Conde, Portugal; Department of Organisms and Systems Biology (Zoology), University of Oviedo, Oviedo, 33071, Spain; Research Unit of Biodiversity (UMIB, UO/CSIC/PA), University of Oviedo, Mieres, Spain.
| | - Frederico M Barroso
- CIBIO, Research Centre in Biodiversity and Genetic Resources, InBIO, Universidade do Porto, Campus de Vairão, Rua Padre Armando Quintas, nº7, Vairão, 4485-661, Vila do Conde, Portugal; Departamento de Biologia, Faculdade de Ciências da Universidade do Porto, R. Campo Alegre, s/n, 4169 - 007, Porto, Portugal
| | - Miguel A Carretero
- CIBIO, Research Centre in Biodiversity and Genetic Resources, InBIO, Universidade do Porto, Campus de Vairão, Rua Padre Armando Quintas, nº7, Vairão, 4485-661, Vila do Conde, Portugal; Departamento de Biologia, Faculdade de Ciências da Universidade do Porto, R. Campo Alegre, s/n, 4169 - 007, Porto, Portugal
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5
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Rozen‐Rechels D, Rutschmann A, DupouÉ A, Blaimont P, Chauveau V, Miles DB, Guillon M, Richard M, Badiane A, Meylan S, Clobert J, Le Galliard J. Interaction of hydric and thermal conditions drive geographic variation in thermoregulation in a widespread lizard. ECOL MONOGR 2021. [DOI: 10.1002/ecm.1440] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- David Rozen‐Rechels
- Sorbonne Université CNRS IRD INRA Institut d’écologie et des sciences de l’environnement (IEES) 4 place Jussieu Paris 75005 France
| | - Alexis Rutschmann
- School of Biological Sciences University of Auckland 3A Symonds Street Auckland 1010 New Zealand
| | - AndrÉaz DupouÉ
- Sorbonne Université CNRS IRD INRA Institut d’écologie et des sciences de l’environnement (IEES) 4 place Jussieu Paris 75005 France
| | - Pauline Blaimont
- Department of Ecology and Evolutionary Biology University of California Santa Cruz 1156 High Street Santa Cruz California 95060 USA
- Department of Biology Rider University 2083 Lawrenceville Road Lawrenceville New Jersey08648 USA
| | - Victor Chauveau
- Sorbonne Université CNRS IRD INRA Institut d’écologie et des sciences de l’environnement (IEES) 4 place Jussieu Paris 75005 France
| | - Donald B. Miles
- Department of Biological Sciences Ohio University Athens Ohio 45701 USA
| | - Michael Guillon
- Centre d’Études Biologiques de Chizé CNRS La Rochelle Université 405 Route de Prissé la Charrière Villiers‐en‐Bois 79360 France
| | - Murielle Richard
- Station d’Ecologie Théorique et Expérimentale (SETE) USR5321CNRS Moulis09200France
| | - Arnaud Badiane
- Sorbonne Université CNRS IRD INRA Institut d’écologie et des sciences de l’environnement (IEES) 4 place Jussieu Paris 75005 France
| | - Sandrine Meylan
- Sorbonne Université CNRS IRD INRA Institut d’écologie et des sciences de l’environnement (IEES) 4 place Jussieu Paris 75005 France
- Sorbonne Université ESPE de Paris 10 rue Molitor Paris 75016 France
| | - Jean Clobert
- Station d’Ecologie Théorique et Expérimentale (SETE) USR5321CNRS Moulis09200France
| | - Jean‐François Le Galliard
- Sorbonne Université CNRS IRD INRA Institut d’écologie et des sciences de l’environnement (IEES) 4 place Jussieu Paris 75005 France
- Département de biologie Ecole normale supérieure Centre de recherche en écologie expérimentale et prédictive (CEREEP‐Ecotron IleDeFrance) CNRS PSL University Saint‐Pierre‐lès‐Nemours 77140 France
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6
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Horváth G, Jiménez‐Robles O, Martín J, López P, De la Riva I, Herczeg G. Linking behavioral thermoregulation, boldness, and individual state in male Carpetan rock lizards. Ecol Evol 2020; 10:10230-10241. [PMID: 33005378 PMCID: PMC7520217 DOI: 10.1002/ece3.6685] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 07/22/2020] [Accepted: 07/27/2020] [Indexed: 02/05/2023] Open
Abstract
Mechanisms affecting consistent interindividual behavioral variation (i.e., animal personality) are of wide scientific interest. In poikilotherms, ambient temperature is one of the most important environmental factors with a direct link to a variety of fitness-related traits. Recent empirical evidence suggests that individual differences in boldness are linked to behavioral thermoregulation strategy in heliothermic species, as individuals are regularly exposed to predators during basking. Here, we tested for links between behavioral thermoregulation strategy, boldness, and individual state in adult males of the high-mountain Carpetan rock lizard (Iberolacerta cyreni). Principal component analysis revealed the following latent links in our data: (i) a positive relationship of activity with relative limb length and color brightness (PC1, 23% variation explained), (ii) a negative relationship of thermoregulatory precision with parasite load and risk-taking (PC2, 20.98% variation explained), and (iii) a negative relationship between preferred body temperature and relative limb length (PC3, 19.23% variation explained). We conclude that differences in boldness and behavioral thermoregulatory strategy could be explained by both stable and labile state variables. The moderate link between behavioral thermoregulatory strategy and risk-taking personality in our system is plausibly the result of differences in reproductive state of individuals or variation in ecological conditions during the breeding season.
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Affiliation(s)
- Gergely Horváth
- Behavioural Ecology GroupDepartment of Systematic Zoology and EcologyEötvös Loránd UniversityBudapestHungary
| | - Octavio Jiménez‐Robles
- Department of Ecology and EvolutionResearch School of BiologyAustralian National UniversityCanberraAustralia
- Department of Biodiversity and Evolutionary BiologyMuseo Nacional de Ciencias NaturalesCSICMadridSpain
| | - José Martín
- Department of Evolutionary EcologyMuseo Nacional de Ciencias NaturalesCSICMadridSpain
| | - Pilar López
- Department of Evolutionary EcologyMuseo Nacional de Ciencias NaturalesCSICMadridSpain
| | - Ignacio De la Riva
- Department of Biodiversity and Evolutionary BiologyMuseo Nacional de Ciencias NaturalesCSICMadridSpain
| | - Gábor Herczeg
- Behavioural Ecology GroupDepartment of Systematic Zoology and EcologyEötvös Loránd UniversityBudapestHungary
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7
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Lymburner A, Blouin‐Demers G. Changes in thermal quality of the environment along an elevational gradient affect investment in thermoregulation by Yarrow’s spiny lizards. J Zool (1987) 2020. [DOI: 10.1111/jzo.12818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- A.H. Lymburner
- Department of Biology University of Ottawa Ottawa Ontario Canada
| | - G. Blouin‐Demers
- Department of Biology University of Ottawa Ottawa Ontario Canada
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8
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Rozen-Rechels D, Farigoule P, Agostini S, Badiane A, Meylan S, Le Galliard JF. Short-term change in water availability influences thermoregulation behaviours in a dry-skinned ectotherm. J Anim Ecol 2020; 89:2099-2110. [PMID: 32535907 DOI: 10.1111/1365-2656.13279] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 05/19/2020] [Indexed: 11/28/2022]
Abstract
Mechanistic models of terrestrial ectotherms predict that climate warming will induce activity restriction due to heat stress and loss of shade, leading to the extinction of numerous populations. Such models rely on the assumption that activity patterns are dictated by simple temperature thresholds independent of changes in water availability. However, changes in water availability may further influence thermoregulation behaviour of ectotherms through dehydration risk perception, changes in water balance or changes in microclimatic conditions. Here, we experimentally assess the interactive effects of thermal conditions and water availability on activity patterns, shade selection and thermoregulation efficiency in a model ectothermic species. Thermoregulation behaviour of adult common lizards Zootoca vivipara was monitored in outdoor mesocosms as we manipulated water availability, providing water as mist in the morning and free-standing water during the daytime. We recorded operative temperatures and micro-meteorological conditions to infer thermal constraints and dehydration risk. Activity and shade selection were better predicted by continuous changes in thermal conditions and dehydration risk, respectively, than by threshold functions. In addition, water supplementation increased activity in males and reduced shade selection in both sexes, most probably as a behavioural response to the perception of a stronger dehydration risk. Water supplementation also influenced the thermal quality of the environment, which in turn altered daily activity patterns and thermoregulation statistics. This demonstrates that dual effects of heat and water stress on activity patterns may lead to stronger activity restriction as a result of climate change than currently predicted.
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Affiliation(s)
- David Rozen-Rechels
- Institut d'écologie et des sciences de l'environnement (IEES), CNRS, IRD, INRA, Sorbonne Université, Paris, France
| | - Pauline Farigoule
- Institut d'écologie et des sciences de l'environnement (IEES), CNRS, IRD, INRA, Sorbonne Université, Paris, France
| | - Simon Agostini
- Centre de recherche en écologie expérimentale et prédictive (CEREEP-Ecotron IleDeFrance), Département de biologie, Ecole normale supérieure, CNRS, PSL University, Saint-Pierre-lès-Nemours, France
| | - Arnaud Badiane
- Institut d'écologie et des sciences de l'environnement (IEES), CNRS, IRD, INRA, Sorbonne Université, Paris, France
| | - Sandrine Meylan
- Institut d'écologie et des sciences de l'environnement (IEES), CNRS, IRD, INRA, Sorbonne Université, Paris, France.,Sorbonne Université, INSPE de Paris, Paris, France
| | - Jean-François Le Galliard
- Institut d'écologie et des sciences de l'environnement (IEES), CNRS, IRD, INRA, Sorbonne Université, Paris, France.,Centre de recherche en écologie expérimentale et prédictive (CEREEP-Ecotron IleDeFrance), Département de biologie, Ecole normale supérieure, CNRS, PSL University, Saint-Pierre-lès-Nemours, France
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9
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Patterson L, Blouin-Demers G. Partial support for food availability and thermal quality as drivers of density and area used in Yarrow’s Spiny Lizards ( Sceloporus jarrovii). CAN J ZOOL 2020. [DOI: 10.1139/cjz-2019-0166] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Contrary to traditional models, habitat selection in ectotherms may be chiefly based on a habitat’s thermal properties rather than its food availability, due to their physiological dependence on environmental temperature. We tested two hypotheses: that microhabitat use in ectotherms is driven by food availability and that it is driven by thermoregulatory requirements. We predicted that the density of lizards would increase and the mean area used would decrease with the natural arthropod (food) availability (or thermal quality) of a plot, as well as after experimentally increasing plot arthropod availability (or thermal quality). We established two plots in each of four treatments (food-supplemented, shaded, food-supplemented and shaded, and control) on a talus slope in Arizona, USA. We measured the density and area used in Yarrow’s Spiny Lizards (Sceloporus jarrovii Cope in Yarrow, 1875) before and after manipulations, and determined whether lizard density and area used were related to natural arthropod availability or thermal quality at the surface and in retreat sites. Density and area used were unaffected by the manipulations, but both increased with natural arthropod availability and decreased with higher thermal quality in retreat sites. These results provide partial support for both food availability and thermal quality as drivers of density and microhabitat use in S. jarrovii.
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Affiliation(s)
- L.D. Patterson
- Department of Biology, University of Ottawa, 30 Marie-Curie Private, Ottawa, ON K1N 6N5, Canada
| | - G. Blouin-Demers
- Department of Biology, University of Ottawa, 30 Marie-Curie Private, Ottawa, ON K1N 6N5, Canada
- Department of Biology, University of Ottawa, 30 Marie-Curie Private, Ottawa, ON K1N 6N5, Canada
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10
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Rozen‐Rechels D, Badiane A, Agostini S, Meylan S, Le Galliard J. Water restriction induces behavioral fight but impairs thermoregulation in a dry‐skinned ectotherm. OIKOS 2020. [DOI: 10.1111/oik.06910] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- David Rozen‐Rechels
- Inst. d'écologie et des sciences de l'environnement (IEES), Sorbonne Univ., CNRS, IRD, INRA 4 Place Jussieu FR‐75252 Paris Cedex 5 France
| | - Arnaud Badiane
- Inst. d'écologie et des sciences de l'environnement (IEES), Sorbonne Univ., CNRS, IRD, INRA 4 Place Jussieu FR‐75252 Paris Cedex 5 France
| | - Simon Agostini
- Centre de recherche en écologie expérimentale et prédictive (CEREEP‐Ecotron IleDeFrance), Dépt de biologie, Ecole normale supérieure, CNRS, PSL Univ. Saint‐Pierre‐lès‐Nemours France
| | - Sandrine Meylan
- Inst. d'écologie et des sciences de l'environnement (IEES), Sorbonne Univ., CNRS, IRD, INRA 4 Place Jussieu FR‐75252 Paris Cedex 5 France
- Sorbonne Université, ESPE de Paris Paris France
| | - Jean‐François Le Galliard
- Inst. d'écologie et des sciences de l'environnement (IEES), Sorbonne Univ., CNRS, IRD, INRA 4 Place Jussieu FR‐75252 Paris Cedex 5 France
- Centre de recherche en écologie expérimentale et prédictive (CEREEP‐Ecotron IleDeFrance), Dépt de biologie, Ecole normale supérieure, CNRS, PSL Univ. Saint‐Pierre‐lès‐Nemours France
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11
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Lymburner AH, Blouin-Demers G. Ornate tree lizards (Urosaurus ornatus) thermoregulate less accurately in habitats of high thermal quality. J Therm Biol 2019; 85:102402. [PMID: 31657742 DOI: 10.1016/j.jtherbio.2019.102402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 08/22/2019] [Accepted: 08/23/2019] [Indexed: 11/24/2022]
Abstract
Temperature plays a critical role for ectotherm performance and thus for fitness. Ectotherms, since unable to regulate their body temperature internally, use behavioural thermoregulation to maintain their body temperature within a range that maximizes performance. According to the cost-benefit model of thermoregulation, investment into thermoregulation is dictated by the trade-off between the costs and benefits of thermoregulating. The thermal quality of the environment is a major cost of thermoregulation because it directly affects the amount of time and energy that must be invested by an individual to achieve and maintain an optimal body temperature. Thus, in habitats of poor thermal quality, lizards should thermoregulate less. Using Urosaurus ornatus living at 10 sites each straddling two adjacent habitats (wash and upland), we tested the hypothesis that investment in thermoregulation is dependent on the thermal quality of the habitat. We found that the wash habitat had higher thermal quality indicated by a longer duration when optimal body temperatures could be reached. Lizards had more accurate body temperatures in the upland despite its poorer thermal quality. These results suggest that discrepancies in thermal quality between adjacent habitats affect investment in thermoregulation by lizards, but in a direction opposite to the main prediction of the cost-benefit model of thermoregulation.
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Affiliation(s)
- Alannah H Lymburner
- Department of Biology, University of Ottawa, 30 Marie-Curie Private, Ottawa, Canada.
| | - Gabriel Blouin-Demers
- Department of Biology, University of Ottawa, 30 Marie-Curie Private, Ottawa, Canada.
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12
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Leirião L, Piantoni C, Ribeiro PL, Navas CA. Independent influence of thermoregulatory cost on the lower and upper set-points of a heliothermic lizard. Behav Processes 2019; 164:17-24. [PMID: 30978389 DOI: 10.1016/j.beproc.2019.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 03/22/2019] [Accepted: 04/02/2019] [Indexed: 11/29/2022]
Abstract
Studies on ectothermic vertebrates generally lead to average indicators of thermal preferences measured in the laboratory, which do not say about responses to natural environmental change and may not inform about individual variation and its triggering mechanisms. We studied whether and how changes in costs of thermoregulation influence the preferred temperature (Tp) of individual lizards and their energetic investment in thermoregulation by exposing specimens to three treatments of increasing costs, recording body temperature (Tb) and distance walked (energetic investment). Moderate costs induced an investment trade-off between energy-investment in thermoregulation and Tb, and highlighted individual variation that decreased with higher costs. Lower average Tp's were observed in the high costs trials as a result of the decreased values of the lower and upper voluntary Tb's. As costs increased, lizards walked a shorter overall distance and accepted lower Tb's, but lizards still engaged in costly thermoregulation. Individual variation resulted in two main thermoregulatory patterns that in certain ecological contexts may have an important role in decision-making and adjusting to temperatures that are far from optimal temperatures for performance and physiological processes.
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Affiliation(s)
- Luciana Leirião
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão Tr. 14 No. 101, CEP 05508-900, São Paulo, SP, Brazil.
| | - Carla Piantoni
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão Tr. 14 No. 101, CEP 05508-900, São Paulo, SP, Brazil.
| | - Pedro L Ribeiro
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão Tr. 14 No. 101, CEP 05508-900, São Paulo, SP, Brazil.
| | - Carlos A Navas
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão Tr. 14 No. 101, CEP 05508-900, São Paulo, SP, Brazil.
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13
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Paterson JE, Blouin-Demers G. Male throat colour polymorphism is related to differences in space use and in habitat selection in tree lizards. J Zool (1987) 2018. [DOI: 10.1111/jzo.12576] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- J. E. Paterson
- Department of Biology; University of Ottawa; Ottawa ON Canada
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14
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Schwanz LE, Hodgson MJ, May A. Costs of thermoregulation in variable thermal environments in the jacky dragon (
Amphibolurus muricatus
). J Zool (1987) 2018. [DOI: 10.1111/jzo.12559] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- L. E. Schwanz
- Evolution & Ecology Research Centre School of Biological, Earth, and Environmental Sciences UNSW Sydney Sydney NSW Australia
| | - M. J. Hodgson
- Evolution & Ecology Research Centre School of Biological, Earth, and Environmental Sciences UNSW Sydney Sydney NSW Australia
| | - A. May
- Evolution & Ecology Research Centre School of Biological, Earth, and Environmental Sciences UNSW Sydney Sydney NSW Australia
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15
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Thermoregulation of a temperate reptile in a forested habitat. ZOOLOGY 2018; 127:63-69. [PMID: 29500060 DOI: 10.1016/j.zool.2018.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 02/01/2018] [Accepted: 02/04/2018] [Indexed: 11/20/2022]
Abstract
A major focus in zoology is to understand the phenotypic responses of animals to environmental variation. This is particularly important when dealing with ectotherms in a thermally heterogenous environment. We measured body temperatures of a free-ranging, medium sized temperate reptile, the tuatara, Sphenodon punctatus, to investigate its thermal opportunities and the degree to which the animal actively regulates its body temperature. We found high variation in body temperature between individuals, but this variation could not be attributed to sex or body size. However, variation among individuals in timing of burrow use did affect body temperature and in one of the years studied tuatara were found to be more effective in their thermoregulation when sharing a burrow with a seabird (Pachyptila turtur). The strength of this study is that it includes both biotic and behavioural components of the thermal environment of a temperate reptile, areas which are often missing from thermal studies that focus on the abiotic aspects.
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16
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Loehr VJT. Thermoregulatory challenges in the habitat of the world's smallest tortoise, Chersobius signatus. J Therm Biol 2018; 71:62-68. [PMID: 29301701 DOI: 10.1016/j.jtherbio.2017.10.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 10/28/2017] [Accepted: 10/30/2017] [Indexed: 11/30/2022]
Abstract
Ectotherms have various means of dealing with low environmental temperatures, but relatively few species have been rigorously investigated. Consequently, we have little information to predict how ectotherm populations might respond to global temperature changes. Tortoises from temperate and subtropical regions often overcome periodically cool conditions by hibernation, but speckled dwarf tortoises (Chersobius signatus) need to remain active to exploit ephemeral resources in their arid winter-rainfall habitat. This study investigated how dwarf tortoises cope with low temperatures in winter and spring, by measuring thermal habitat quality and thermoregulation based on differently-sized operative temperature models in sun, shade, and in deep crevices. Investigations continued in summer and autumn to obtain a year-round picture of thermoregulatory challenges. Although large models (i.e., larger than dwarf tortoises) were expected to have lower operative temperatures than smaller models, due to the former's larger thermal inertia, all model sizes had similar temperatures. Hence, the species' small body size does not appear constrained by obtainable body temperatures in cool seasons. Nevertheless, low operative temperatures in winter posed a challenge for the tortoises, which reached their field-preferred body temperature for an average of only 0.8-0.9h per day. Moreover, a low thermoregulation effectiveness suggested that tortoises traded-off physiological benefits of favourable body temperatures against predation risk. Spring and autumn provided higher temperatures, but summer caused the greatest thermoregulatory challenge. Although summer body temperatures were closer to field-preferred body temperature than in any other season, tortoises required rock crevices to avoid overheating. The small size of dwarf tortoises might help them utilise crevices. In summer, maximum operative temperatures in crevices were similar to field-preferred body temperature, indicating that an increase in environmental temperatures might be detrimental to dwarf tortoises. In light of projected temperature rises, future studies should assess if dwarf tortoises can cope with higher environmental temperatures in summer.
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Affiliation(s)
- Victor J T Loehr
- Homopus Research Foundation, Kwikstaartpad 1, 3403ZH IJsselstein, The Netherlands.
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17
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Altitude influences thermal ecology and thermal sensitivity of locomotor performance in a toad-headed lizard. J Therm Biol 2017; 71:136-141. [PMID: 29301682 DOI: 10.1016/j.jtherbio.2017.11.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 10/31/2017] [Accepted: 11/12/2017] [Indexed: 11/21/2022]
Abstract
Population differentiation in ectotherm physiological performance may be driven by adapting to different thermal environments. In this study, we measured locomotor performance in two different altitude populations of the Qinghai toad-headed lizards (Phrynocephalus vlangalii) at different test temperatures to assess between-population differences in thermal sensitivity of sprint speed. Low-elevation lizards ran faster than high-elevation lizards at most test temperatures. Sprint speed varied with test temperature similarly between populations, but the thermal sensitivity (performance breadth) differed significantly. Low-elevation lizards had a lower optimal temperature (Topt) for sprint speed and narrower performance breadth than high-elevation lizards as inferred from the thermal performance curves constructed for each individual. We also measured the body temperature of active lizards (Tb) in the field and selected temperature (Tsel) in the laboratory. Low-elevation lizards had a lower Tsel, and less variable Tb than high-elevation lizards. In both populations, Tsel was lower than Topt for sprint speed, which was inconsistent with the prediction for a match between thermal preference and Topt. Our results suggest that lower thermal sensitivity and weaker locomotor ability for high-elevation lizards may be an adaptive response to the local environmental conditions (e.g., greater thermal variability, higher food availability, and lower predator pressure).
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18
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Paterson JE, Blouin-Demers G. Density-dependent habitat selection predicts fitness and abundance in a small lizard. OIKOS 2017. [DOI: 10.1111/oik.04758] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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19
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Patterson LD, Darveau CA, Blouin-Demers G. Support for the thermal coadaptation hypothesis from the growth rates of Sceloporus jarrovii lizards. J Therm Biol 2017; 70:86-96. [PMID: 29108562 DOI: 10.1016/j.jtherbio.2017.09.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 07/28/2017] [Accepted: 09/26/2017] [Indexed: 11/25/2022]
Abstract
The thermal coadaptation hypothesis posits that ectotherms thermoregulate behaviorally to maintain body temperatures (Tb) that maximize performance, such as net energy gain. Huey's (1982) energetics model describes how food availability and Tb interact to affect net energy gain. We tested the thermal coadaptation hypothesis and Huey's energetics model with growth rates of juvenile Yarrow's spiny lizards (Sceloporus jarrovii). We compared the preferred (selected) Tb range (Tsel) of lizards in high and low energy states to their optimal temperature (To) for growth over nine weeks, and determined whether the To for growth depended on food availability. We also measured the same lizards' resting metabolic rate at five Tbs to test the energetics model assumptions that metabolic cost increases exponentially with Tb and does not differ between energy states. The Tsel of lizards on both diets overlapped with the To for growth. The assumptions of the energetics model were verified, but the To for net energy gain did not depend on food availability. Therefore, we found support for the thermal coadaptation hypothesis. We did not find support for the energetics model, but this may have been due to low statistical power.
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Affiliation(s)
- L D Patterson
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, Canada K1N 6N5.
| | - C-A Darveau
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, Canada K1N 6N5.
| | - G Blouin-Demers
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, Canada K1N 6N5.
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20
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Environment-dependence of behavioural consistency in adult male European green lizards (Lacerta viridis). PLoS One 2017; 12:e0187657. [PMID: 29112964 PMCID: PMC5675404 DOI: 10.1371/journal.pone.0187657] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 10/24/2017] [Indexed: 11/19/2022] Open
Abstract
Understanding the background mechanisms affecting the emergence and maintenance of consistent between-individual variation within population in single (animal personality) or across multiple (behavioural syndrome) behaviours has key importance. State-dependence theory suggests that behaviour is ‘anchored’ to individual state (e.g. body condition, gender, age) and behavioural consistency emerges through behavioural-state feedbacks. A number of relevant state variables are labile (e.g. body condition, physiological performance) and expected to be affected by short-term environmental change. Yet, whether short-term environmental shifts affect behavioural consistency during adulthood remains questionable. Here, by employing a full-factorial laboratory experiment, we explored if quantity of food (low vs. high) and time available for thermoregulation (3h vs. 10h per day) had an effect on activity and risk-taking of reproductive adult male European green lizards (Lacerta viridis). We focussed on different components of behavioural variation: (i) strength of behavioural consistency (repeatability for animal personality; between-individual correlation for behavioural syndrome), (ii) behavioural type (individual mean behaviour) and (iii) behavioural predictability (within-individual behavioural variation). Activity was repeatable in all treatments. Risk-taking was repeatable only in the low basking treatments. We found significant between-individual correlation only in the low food × long basking time group. The treatments did not affect behavioural type, but affected behavioural predictability. Activity predictability was higher in the short basking treatment, where it also decreased with size (≈ age). Risk-taking predictability in the short basking treatment increased with size under food limitation, but decreased when food supply was high. We conclude that short-term environmental change can alter various components of behavioural consistency. The effect could be detected in the presence/absence patterns of animal personality and behavioural syndrome and the level of individual behavioural predictability, but not in behavioural type.
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21
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Camacho A, Rusch TW. Methods and pitfalls of measuring thermal preference and tolerance in lizards. J Therm Biol 2017; 68:63-72. [PMID: 28689723 DOI: 10.1016/j.jtherbio.2017.03.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 03/16/2017] [Accepted: 03/19/2017] [Indexed: 11/28/2022]
Abstract
Understanding methodological and biological sources of bias during the measurement of thermal parameters is essential for the advancement of thermal biology. For more than a century, studies on lizards have deepened our understanding of thermal ecophysiology, employing multiple methods to measure thermal preferences and tolerances. We reviewed 129 articles concerned with measuring preferred body temperature (PBT), voluntary thermal tolerance, and critical temperatures of lizards to offer: a) an overview of the methods used to measure and report these parameters, b) a summary of the methodological and biological factors affecting thermal preference and tolerance, c) recommendations to avoid identified pitfalls, and d) directions for continued progress in our application and understanding of these thermal parameters. We emphasize the need for more methodological and comparative studies. Lastly, we urge researchers to provide more detailed methodological descriptions and suggest ways to make their raw data more informative to increase the utility of thermal biology studies.
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Affiliation(s)
- Agustín Camacho
- Laboratório de Herpetologia, Instituto de Biociências, Universidade de São Paulo, Brazil.
| | - Travis W Rusch
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
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22
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Spontaneous magnetic alignment behaviour in free-living lizards. THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 2017; 104:13. [DOI: 10.1007/s00114-017-1439-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 01/30/2017] [Accepted: 02/01/2017] [Indexed: 11/25/2022]
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23
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Horváth G, Martín J, López P, Garamszegi LZ, Herczeg G. Food and vitamin D3 availability affects lizard personalities: an experiment. Behav Ecol Sociobiol 2016. [DOI: 10.1007/s00265-016-2257-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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24
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Basson CH, Levy O, Angilletta MJ, Clusella‐Trullas S. Lizards paid a greater opportunity cost to thermoregulate in a less heterogeneous environment. Funct Ecol 2016. [DOI: 10.1111/1365-2435.12795] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Christine H. Basson
- Centre for Invasion Biology Department of Botany and Zoology Stellenbosch University Private Bag X1 Matieland7602 South Africa
| | - Ofir Levy
- School of Life Sciences Arizona State University Tempe AZ85287 USA
| | | | - Susana Clusella‐Trullas
- Centre for Invasion Biology Department of Botany and Zoology Stellenbosch University Private Bag X1 Matieland7602 South Africa
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25
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Landry Yuan F, Pickett EJ, Bonebrake TC. Cooler performance breadth in a viviparous skink relative to its oviparous congener. J Therm Biol 2016; 61:106-114. [DOI: 10.1016/j.jtherbio.2016.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 09/01/2016] [Accepted: 09/02/2016] [Indexed: 10/21/2022]
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26
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Bouazza A, Slimani T, El Mouden H, Blouin‐Demers G, Lourdais O. Thermal constraints and the influence of reproduction on thermoregulation in a high‐altitude gecko (
Quedenfeldtia trachyblepharus
). J Zool (1987) 2016. [DOI: 10.1111/jzo.12353] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A. Bouazza
- Laboratoire Biodiversité et Dynamique des Écosystèmes Faculté des Sciences Semlalia Université Cadi Ayyad Marrakech Maroc
| | - T. Slimani
- Laboratoire Biodiversité et Dynamique des Écosystèmes Faculté des Sciences Semlalia Université Cadi Ayyad Marrakech Maroc
| | - H. El Mouden
- Laboratoire Biodiversité et Dynamique des Écosystèmes Faculté des Sciences Semlalia Université Cadi Ayyad Marrakech Maroc
| | - G. Blouin‐Demers
- Département de Biologie Université d'Ottawa Ottawa Ontario Canada
| | - O. Lourdais
- Centre d'Études Biologiques de Chizé UMR 7372 Centre National de la Recherche Scientifique Villiers en Bois France
- School of Life Sciences Arizona State University Tempe AZ USA
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27
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Zamora-Camacho FJ, Reguera S, Moreno-Rueda G. Thermoregulation in the lizard Psammodromus algirus along a 2200-m elevational gradient in Sierra Nevada (Spain). INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2016; 60:687-697. [PMID: 26373651 DOI: 10.1007/s00484-015-1063-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 09/03/2015] [Accepted: 09/07/2015] [Indexed: 06/05/2023]
Abstract
Achieving optimal body temperature maximizes animal fitness. Since ambient temperature may limit ectotherm thermal performance, it can be constrained in too cold or hot environments. In this sense, elevational gradients encompass contrasting thermal environments. In thermally pauperized elevations, ectotherms may either show adaptations or suboptimal body temperatures. Also, reproductive condition may affect thermal needs. Herein, we examined different thermal ecology and physiology capabilities of the lizard Psammodromus algirus along a 2200-m elevational gradient. We measured field (T(b)) and laboratory-preferred (T(pref)) body temperatures of lizards with different reproductive conditions, as well as ambient (T(a)) and copper-model operative temperature (T(e)), which we used to determine thermal quality of the habitat (d(e)), accuracy (d(b)), and effectiveness of thermoregulation (de-db) indexes. We detected no Tb trend in elevation, while T(a) constrained T(b) only at high elevations. Moreover, while Ta decreased more than 7 °C with elevation, T(pref) dropped only 0.6 °C, although significantly. Notably, low-elevation lizards faced excess temperature (T(e) > T(pref)). Notably, de was best at middle elevations, followed by high elevations, and poorest at low elevations. Nonetheless, regarding microhabitat, high-elevation de was more suitable in sun-exposed microhabitats, which may increase exposition to predators, and at midday, which may limit daily activity. As for gender, d(b) and d(e)-d(b) were better in females than in males. In conclusion, P. algirus seems capable to face a wide thermal range, which probably contributes to its extensive corology and makes it adaptable to climate changes.
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Affiliation(s)
| | - Senda Reguera
- Departamento de Zoología, Facultad de Ciencias, Universidad de Granada, 18071, Granada, Spain
| | - Gregorio Moreno-Rueda
- Departamento de Zoología, Facultad de Ciencias, Universidad de Granada, 18071, Granada, Spain
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28
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Gilbert AL, Miles DB. Food, temperature and endurance: effects of food deprivation on the thermal sensitivity of physiological performance. Funct Ecol 2016. [DOI: 10.1111/1365-2435.12658] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Anthony L. Gilbert
- Department of Biological Sciences Ohio University Athens OH USA
- Ohio Center for Ecological and Evolutionary Studies Athens OH USA
| | - Donald B. Miles
- Department of Biological Sciences Ohio University Athens OH USA
- Ohio Center for Ecological and Evolutionary Studies Athens OH USA
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29
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Porter WR, Witmer LM. Vascular Patterns in Iguanas and Other Squamates: Blood Vessels and Sites of Thermal Exchange. PLoS One 2015; 10:e0139215. [PMID: 26466378 PMCID: PMC4605690 DOI: 10.1371/journal.pone.0139215] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 09/10/2015] [Indexed: 11/18/2022] Open
Abstract
Squamates use the circulatory system to regulate body and head temperatures during both heating and cooling. The flexibility of this system, which possibly exceeds that of endotherms, offers a number of physiological mechanisms to gain or retain heat (e.g., increase peripheral blood flow and heart rate, cooling the head to prolong basking time for the body) as well as to shed heat (modulate peripheral blood flow, expose sites of thermal exchange). Squamates also have the ability to establish and maintain the same head-to-body temperature differential that birds, crocodilians, and mammals demonstrate, but without a discrete rete or other vascular physiological device. Squamates offer important anatomical and phylogenetic evidence for the inference of the blood vessels of dinosaurs and other extinct archosaurs in that they shed light on the basal diapsid condition. Given this basal positioning, squamates likewise inform and constrain the range of physiological thermoregulatory mechanisms that may have been found in Dinosauria. Unfortunately, the literature on squamate vascular anatomy is limited. Cephalic vascular anatomy of green iguanas (Iguana iguana) was investigated using a differential-contrast, dual-vascular injection (DCDVI) technique and high-resolution X-ray microcomputed tomography (μCT). Blood vessels were digitally segmented to create a surface representation of vascular pathways. Known sites of thermal exchange, consisting of the oral, nasal, and orbital regions, were given special attention due to their role in brain and cephalic thermoregulation. Blood vessels to and from sites of thermal exchange were investigated to detect conserved vascular patterns and to assess their ability to deliver cooled blood to the dural venous sinuses. Arteries within sites of thermal exchange were found to deliver blood directly and through collateral pathways. The venous drainage was found to have multiple pathways that could influence neurosensory tissue temperature, as well as pathways that would bypass neurosensory tissues. The orbital region houses a large venous sinus that receives cooled blood from the nasal region. Blood vessels from the nasal region and orbital sinus show anastomotic connections to the dural sinus system, allowing for the direct modulation of brain temperatures. The generality of the vascular patterns discovered in iguanas were assessed by firsthand comparison with other squamates taxa (e.g., via dissection and osteological study) as well as the literature. Similar to extant archosaurs, iguanas and other squamates have highly vascularized sites of thermal exchange that likely support physiological thermoregulation that "fine tunes" temperatures attained through behavioral thermoregulation.
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Affiliation(s)
- William Ruger Porter
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, United States of America
| | - Lawrence M. Witmer
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, United States of America
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30
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Artacho P, Saravia J, Ferrandière BD, Perret S, Le Galliard JF. Quantification of correlational selection on thermal physiology, thermoregulatory behavior, and energy metabolism in lizards. Ecol Evol 2015; 5:3600-9. [PMID: 26380689 PMCID: PMC4567864 DOI: 10.1002/ece3.1548] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 04/28/2015] [Accepted: 05/01/2015] [Indexed: 11/11/2022] Open
Abstract
Phenotypic selection is widely accepted as the primary cause of adaptive evolution in natural populations, but selection on complex functional properties linking physiology, behavior, and morphology has been rarely quantified. In ectotherms, correlational selection on thermal physiology, thermoregulatory behavior, and energy metabolism is of special interest because of their potential coadaptation. We quantified phenotypic selection on thermal sensitivity of locomotor performance (sprint speed), thermal preferences, and resting metabolic rate in captive populations of an ectothermic vertebrate, the common lizard, Zootoca vivipara. No correlational selection between thermal sensitivity of performance, thermoregulatory behavior, and energy metabolism was found. A combination of high body mass and resting metabolic rate was positively correlated with survival and negatively correlated with fecundity. Thus, different mechanisms underlie selection on metabolism in lizards with small body mass than in lizards with high body mass. In addition, lizards that selected the near average preferred body temperature grew faster that their congeners. This is one of the few studies that quantifies significant correlational selection on a proxy of energy expenditure and stabilizing selection on thermoregulatory behavior.
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Affiliation(s)
- Paulina Artacho
- Instituto de Ciencias Ambientales y Evolutivas, Campus Isla Teja, Universidad Austral de ChileValdivia, Chile
- CNRS, UMR 7618, iEES Paris, Université Pierre et Marie Curie7 Quai St. Bernard, 75005, Paris, France
| | - Julia Saravia
- Instituto de Ciencias Ambientales y Evolutivas, Campus Isla Teja, Universidad Austral de ChileValdivia, Chile
- CNRS, UMR 7618, iEES Paris, Université Pierre et Marie Curie7 Quai St. Bernard, 75005, Paris, France
| | - Beatriz Decencière Ferrandière
- Instituto de Ciencias Ambientales y Evolutivas, Campus Isla Teja, Universidad Austral de ChileValdivia, Chile
- CNRS/ENS UMS 3194, CEREEP – Ecotron IleDeFrance, École Normale Supérieure78 rue du Château, 77140, St-Pierre-lès-Nemours, France
| | - Samuel Perret
- Instituto de Ciencias Ambientales y Evolutivas, Campus Isla Teja, Universidad Austral de ChileValdivia, Chile
- CNRS/ENS UMS 3194, CEREEP – Ecotron IleDeFrance, École Normale Supérieure78 rue du Château, 77140, St-Pierre-lès-Nemours, France
| | - Jean-François Le Galliard
- CNRS, UMR 7618, iEES Paris, Université Pierre et Marie Curie7 Quai St. Bernard, 75005, Paris, France
- CNRS/ENS UMS 3194, CEREEP – Ecotron IleDeFrance, École Normale Supérieure78 rue du Château, 77140, St-Pierre-lès-Nemours, France
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31
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Piasečná K, Pončová A, Tejedo M, Gvoždík L. Thermoregulatory strategies in an aquatic ectotherm from thermally-constrained habitats: An evaluation of current approaches. J Therm Biol 2015; 52:97-107. [PMID: 26267504 DOI: 10.1016/j.jtherbio.2015.06.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 06/10/2015] [Accepted: 06/12/2015] [Indexed: 11/15/2022]
Abstract
Many ectotherms employ diverse behavioral adjustments to effectively buffer the spatio-temporal variation in environmental temperatures, whereas others remain passive to thermal heterogeneity. Thermoregulatory studies are frequently performed on species living in thermally benign habitats, which complicate understanding of the thermoregulation-thermoconformity continuum. The need for new empirical data from ectotherms exposed to thermally challenging conditions requires the evaluation of available methods for quantifying thermoregulatory strategies. We evaluated the applicability of various thermoregulatory indices using fire salamander larvae, Salamandra salamandra, in two aquatic habitats, a forest pool and well, as examples of disparate thermally-constrained environments. Water temperatures in the well were lower and less variable than in the pool. Thermal conditions prevented larvae from reaching their preferred body temperature range in both water bodies. In contrast to their thermoregulatory abilities examined in a laboratory thermal gradient, field body temperatures only matched the mean and range of operative temperatures, showing thermal passivity of larvae in both habitats. Despite apparent thermoconformity, thermoregulatory indices indicated various strategies from active thermoregulation, to thermoconformity, and even thermal evasion, which revealed their limited applicability under thermally-constrained conditions. Salamander larvae abandoned behavioral thermoregulation despite varying opportunities to increase their body temperature above average water temperatures. Thermoconformity represents a favored strategy in these ectotherms living in more thermally-constrained environments than those examined in previous thermoregulatory studies. To understand thermal ecology and its impact on population dynamics, the quantification of thermoregulatory strategies of ectotherms in thermally-constrained habitats requires the careful choice of an appropriate method to avoid misleading results.
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Affiliation(s)
- Karin Piasečná
- Institute of Vertebrate Biology AS CR, Květná 8, 60365 Brno, Czech Republic
| | - Alena Pončová
- Czech Union for Nature Conservation, V Zálomu 2948/1, 70030 Ostrava, Czech Republic
| | - Miguel Tejedo
- Department of Evolutionary Ecology, Estación Biológica de Doñana, CSIC, Americo Vespucio, 41092 Sevilla, Spain
| | - Lumír Gvoždík
- Institute of Vertebrate Biology AS CR, Květná 8, 60365 Brno, Czech Republic.
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Zamora‐Camacho FJ, Reguera S, Moreno‐Rueda G. Does tail autotomy affect thermoregulation in an accurately thermoregulating lizard? Lessons from a 2200‐m elevational gradient. J Zool (1987) 2015. [DOI: 10.1111/jzo.12266] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- F. J. Zamora‐Camacho
- Departamento de Zoología, Facultad de Ciencias Universidad de Granada Granada Spain
| | - S. Reguera
- Departamento de Zoología, Facultad de Ciencias Universidad de Granada Granada Spain
| | - G. Moreno‐Rueda
- Departamento de Zoología, Facultad de Ciencias Universidad de Granada Granada Spain
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Siliceo-Cantero HH, García A. Actividad y uso del hábitat de una población insular y una continental de lagartijas Anolis nebulosus (Squamata: Polychrotidae) en un ambiente estacional. REV MEX BIODIVERS 2015. [DOI: 10.1016/j.rmb.2015.04.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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34
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Tan WC, Schwanz LE. Thermoregulation across thermal environments in a nocturnal gecko. J Zool (1987) 2015. [DOI: 10.1111/jzo.12235] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- W. C. Tan
- Division of Evolution; Ecology and Genetics; Research School of Biology; Australian National University; Canberra ACT Australia
| | - L. E. Schwanz
- Division of Evolution; Ecology and Genetics; Research School of Biology; Australian National University; Canberra ACT Australia
- Evolution and Ecology Research Centre; School of Biological; Earth and Environmental Sciences; University of New South Wales; Sydney NSW Australia
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Aguado S, Braña F. Thermoregulation in a cold-adapted species (Cyren’s Rock Lizard, Iberolacerta cyreni): influence of thermal environment and associated costs. CAN J ZOOL 2014. [DOI: 10.1139/cjz-2014-0096] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Thermal constraints may limit the physiology and behaviour of ectotherms because of the high thermal dependence of metabolic functions. The adaptive mechanisms of thermoregulation and the cost of confronting thermal constraints were studied in the Cyren’s Rock Lizard (Iberolacerta cyreni (Müller and Hellmich, 1937)), a lacertid lizard endemic to mountain areas of central Spain. Semicontinuous monitoring of body temperature (Tb) in the laboratory indicated that the preferred temperature range for this population (Tpref) was lower than those found for most lacertid lizards, and field body temperatures of active animals in summer were even lower than Tpref. Overall these results, together with distribution of field operative temperatures (Te), indicate that I. cyreni is an active and relatively accurate thermoregulator, although limited by thermal constraints in their habitat. Laboratory experiments in contrasting thermal environments showed that even under thermally restricted conditions, lizards achieved their Tpref by modifying their thermoregulatory behaviour, principally through changes in space use, basking time, and body posture. However, these behavioural adjustments to reach the Tpref have associated costs, and lizards spent 80% of their time in thermoregulation when tested under low radiation conditions, which in the wild would limit the scope for other activities and eventually increase predation risk. Our results suggest that thermoregulatory behaviour may play an important role in coping with global climate change, hence predictions of the effects of climate warming on lizards inhabiting cold habitats should take into account the buffering role of behavioural thermoregulation.
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Affiliation(s)
- S. Aguado
- Unidad de Zoología, Departamento de Biología de Organismos y Sistemas, Universidad de Oviedo, and Unidad Mixta de Investigación en Biodiversidad (UMIB, CSIC-UO-PA), c/ Catedrático Rodrigo Uría s/n, 33071 Oviedo, Spain
| | - F. Braña
- Unidad de Zoología, Departamento de Biología de Organismos y Sistemas, Universidad de Oviedo, and Unidad Mixta de Investigación en Biodiversidad (UMIB, CSIC-UO-PA), c/ Catedrático Rodrigo Uría s/n, 33071 Oviedo, Spain
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Goller M, Goller F, French SS. A heterogeneous thermal environment enables remarkable behavioral thermoregulation in Uta stansburiana. Ecol Evol 2014; 4:3319-29. [PMID: 25535549 PMCID: PMC4228607 DOI: 10.1002/ece3.1141] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 05/16/2014] [Accepted: 05/27/2014] [Indexed: 11/18/2022] Open
Abstract
Ectotherms can attain preferred body temperatures by selecting specific temperature microhabitats within a varied thermal environment. The side-blotched lizard, Uta stansburiana may employ microhabitat selection to thermoregulate behaviorally. It is unknown to what degree habitat structural complexity provides thermal microhabitats for thermoregulation. Thermal microhabitat structure, lizard temperature, and substrate preference were simultaneously evaluated using thermal imaging. A broad range of microhabitat temperatures was available (mean range of 11°C within 1-2 m(2)) while mean lizard temperature was between 36°C and 38°C. Lizards selected sites that differed significantly from the mean environmental temperature, indicating behavioral thermoregulation, and maintained a temperature significantly above that of their perch (mean difference of 2.6°C). Uta's thermoregulatory potential within a complex thermal microhabitat structure suggests that a warming trend may prove advantageous, rather than detrimental for this population.
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Affiliation(s)
- Maria Goller
- Department of Biology, Utah State UniversityLogan, Utah, 84322-5305
| | - Franz Goller
- Department of Biology, University of UtahSalt Lake City, Utah, 84112-0840
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Differences in growth rate, body condition, habitat use and food availability between island and mainland lizard populations ofAnolis nebulosusin Jalisco, Mexico. JOURNAL OF TROPICAL ECOLOGY 2014. [DOI: 10.1017/s0266467414000297] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Abstract:Lizards of the genusAnolishave been widely studied, however, little is known about the effects of environmental seasonality, food availability and geographic isolation on body condition, growth rate and habitat use of lizards. The existence of an insular and a continental population ofAnolis nebulosus(clouded anole), separated by only 0.47 km, represents an ideal opportunity to address this topic. We compared seasonal fluctuations in food availability (arthropod density) for anoles, as well as body condition, growth rate and habitat use in the two populations. Food availability throughout the year was sampled every 2 mo by trapping arthropods at each site. Lizards were also monitored and measured every 2 mo by surveying three quadrats in each site over 2 y giving a total of 30 visits for each quadrat. Results suggested that composition and density of food supply was similar for the two populations. Nevertheless, food supply responded to seasonality of rainfall, with an increase of 1.5 times during the rainy season. Despite similarity in food availability, insular anoles had body condition that was 5–10 times better, with growth rate twice as fast, and used similar perches. The role of predation, and inter- and intraspecific competition are discussed as possible drivers.
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38
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Artacho P, Jouanneau I, Le Galliard JF. Interindividual Variation in Thermal Sensitivity of Maximal Sprint Speed, Thermal Behavior, and Resting Metabolic Rate in a Lizard. Physiol Biochem Zool 2013; 86:458-69. [DOI: 10.1086/671376] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Brewster CL, Sikes RS, Gifford ME. Quantifying the cost of thermoregulation: thermal and energetic constraints on growth rates in hatchling lizards. Funct Ecol 2013. [DOI: 10.1111/1365-2435.12066] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Casey L. Brewster
- Department of Biology University of Arkansas at Little Rock Little Rock AR 72204 USA
| | - Robert S. Sikes
- Department of Biology University of Arkansas at Little Rock Little Rock AR 72204 USA
| | - Matthew E. Gifford
- Department of Biology University of Arkansas at Little Rock Little Rock AR 72204 USA
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40
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Meylan S, Richard M, Bauer S, Haussy C, Miles D. Costs of Mounting an Immune Response during Pregnancy in a Lizard. Physiol Biochem Zool 2013; 86:127-36. [DOI: 10.1086/668637] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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41
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BLEU J, HEULIN B, HAUSSY C, MEYLAN S, MASSOT M. Experimental evidence of early costs of reproduction in conspecific viviparous and oviparous lizards. J Evol Biol 2012; 25:1264-74. [DOI: 10.1111/j.1420-9101.2012.02518.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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42
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Alford JG, Lutterschmidt WI. Modeling energetic and theoretical costs of thermoregulatory strategy. JOURNAL OF BIOLOGICAL DYNAMICS 2011; 6:63-79. [PMID: 22873523 DOI: 10.1080/17513758.2011.588342] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Poikilothermic ectotherms have evolved behaviours that help them maintain or regulate their body temperature (T (b)) around a preferred or 'set point' temperature (T (set)). Thermoregulatory behaviors may range from body positioning to optimize heat gain to shuttling among preferred microhabitats to find appropriate environmental temperatures. We have modelled movement patterns between an active and non-active shuttling behaviour within a habitat (as a biased random walk) to investigate the potential cost of two thermoregulatory strategies. Generally, small-bodied ectotherms actively thermoregulate while large-bodied ectotherms may passively thermoconform to their environment. We were interested in the potential energetic cost for a large-bodied ectotherm if it were forced to actively thermoregulate rather than thermoconform. We therefore modelled movements and the resulting and comparative energetic costs in precisely maintaining a T (set) for a small-bodied versus large-bodied ectotherm to study and evaluate the thermoregulatory strategy.
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Affiliation(s)
- John G Alford
- Departments of Mathematics and Statistics, Sam Houston State University, Huntsville, TX 77341, USA.
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43
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Vickers M, Manicom C, Schwarzkopf L. Extending the Cost-Benefit Model of Thermoregulation: High-Temperature Environments. Am Nat 2011; 177:452-61. [PMID: 21460567 DOI: 10.1086/658150] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Mathew Vickers
- School of Marine and Tropical Biology, James Cook University, Townsville, Queensland 4811, Australia.
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Schuler MS, Sears MW, Angilletta MJ. Food consumption does not affect the preferred body temperature of Yarrow's spiny lizard (Sceloporus jarrovi). J Therm Biol 2011. [DOI: 10.1016/j.jtherbio.2010.12.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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45
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Khan JJ, Richardson JM, Tattersall GJ. Thermoregulation and aggregation in neonatal bearded dragons (Pogona vitticeps). Physiol Behav 2010; 100:180-6. [DOI: 10.1016/j.physbeh.2010.02.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Revised: 02/19/2010] [Accepted: 02/19/2010] [Indexed: 10/19/2022]
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46
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A cold-adapted reptile becomes a more effective thermoregulator in a thermally challenging environment. Oecologia 2010; 163:571-81. [PMID: 20140685 DOI: 10.1007/s00442-010-1571-y] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Accepted: 01/12/2010] [Indexed: 10/19/2022]
Abstract
Thermoregulation is of great importance for the survival and fitness of ectotherms as physiological functions are optimized within a narrow range of body temperature (T(b)). The precision with which reptiles thermoregulate has been proposed to be related to the thermal quality of their environments. Although a number of studies have looked at the effect of thermal constraints imposed by diel, seasonal and altitudinal variation on thermoregulatory strategies, few have addressed this question in a laboratory setting. We conducted a laboratory experiment to test whether tuatara, Sphenodon punctatus (order Rhynchocephalia), a cold-adapted reptile endemic to New Zealand, modify their thermoregulatory behaviour in response to different thermal environments. We provided tuatara with three thermal treatments: high-quality habitat [preferred T(b) (T(sel)) could be reached for 8 h/day], medium-quality habitat (T(sel) available for 5 h/day) and low-quality habitat (T(sel) available for 3 h/day). All groups maintained body mass, but tuatara in the low-quality habitat thermoregulated more accurately and tended to maintain higher T (b)s than tuatara in the high-quality habitat. This study thus provides experimental evidence that reptiles are capable of adjusting their thermoregulatory behaviour in response to different thermal constraints. This result also has implications for the conservation of tuatara. A proposed translocation from their current habitat to a higher latitudinal range within New Zealand (similar to the shift from our 8 h/day to our 5 h/day regime) is unlikely to induce thermoconformity; rather, tuatara will probably engage in more effective thermoregulatory behaviour.
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47
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Karsten KB, Ferguson GW, Chen TC, Holick MF. Panther chameleons, Furcifer pardalis, behaviorally regulate optimal exposure to UV depending on dietary vitamin D3 status. Physiol Biochem Zool 2009; 82:218-25. [PMID: 19335229 DOI: 10.1086/597525] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Reptiles may bask for reasons other than thermoregulation. One alternative is to regulate homeostasis of vitamin D(3), a hormone essential to the health of many reptiles. Maintenance of vitamin D(3) homeostasis requires either regulation of exposure to ultraviolet radiation (UV) or ingested vitamin D(3). However, the prey items of most vertebrates tend to be low in vitamin D(3). Thus, basking may be the primary opportunity for vitamin D(3) regulation. We tested the hypothesis that panther chameleons (Furcifer pardalis) behaviorally regulate exposure to UV in natural sunlight with high precision, accuracy, and effectiveness. Panther chameleons with low dietary vitamin D(3) intake significantly increased exposure to UV in natural sunlight compared to those with high dietary vitamin D(3) intake. All lizards fed low dietary vitamin D(3) regulated within optimal UV levels with extreme effectiveness (ability to regulate within optimal UV levels relative to available UV). Chameleons of both dietary treatments regulated UV exposure with great precision, exhibiting little variation among individuals within treatments. Our results add to a growing body of literature that empirically demonstrates the importance of basking for nonthermoregulatory purposes and, more specifically, as an integral mechanism for the regulation of a vital hormone, vitamin D(3).
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Affiliation(s)
- Kristopher B Karsten
- Department of Biology, Texas Christian University, Fort Worth, Texas 76129, USA.
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48
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Cadena V, Tattersall G. The Effect of Thermal Quality on the Thermoregulatory Behavior of the Bearded DragonPogona vitticeps: Influences of Methodological Assessment. Physiol Biochem Zool 2009; 82:203-17. [DOI: 10.1086/597483] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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49
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Child T, Phillips BL, Shine R. Abiotic and biotic influences on the dispersal behavior of metamorph cane toads (Bufo marinus) in tropical Australia. ACTA ACUST UNITED AC 2008; 309:215-24. [PMID: 18288694 DOI: 10.1002/jez.450] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A mechanistic understanding of factors influencing the dispersal behavior of metamorph cane toads (Bufo marinus) has direct conservation relevance in Australia. These invasive anurans are toxic to native predators, and if we can predict their distribution across the landscape, we can also predict (and perhaps, manage) the scale of their impact. We propose that the major drivers of metamorph distribution are the risk of dehydration (restricting the young toads to moist substrates near pond margins) and biotic advantages to dispersal away from the pond (especially, less risk of cannibalism). To test this model, we investigated the influence of abiotic and biotic cues on the behavior of individual toads in the laboratory. Substrate moisture levels strongly influenced metamorph activity levels and habitat selection: dry substrates induced most metamorphs to remain near water. The only biotic cue to influence metamorph dispersal was proximity of a larger (cannibalistic) conspecific; a cannibal's presence at the pond margin caused most metamorphs to spend less time there, and as a consequence, to dehydrate more rapidly. Our results suggest that the spatial and temporal distribution of metamorph cane toads reflects a trade-off between competing risks: the danger of desiccation tends to keep young toads close to the pond margin in dry conditions, whereas the danger of cannibalism stimulates dispersal.
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Affiliation(s)
- Travis Child
- School of Biological Sciences A08, University of Sydney, Sydney, NSW, Australia
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50
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Martin T, Huey R. Why “Suboptimal” Is Optimal: Jensen’s Inequality and Ectotherm Thermal Preferences. Am Nat 2008; 171:E102-18. [DOI: 10.1086/527502] [Citation(s) in RCA: 440] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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