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Azzolini JL, Pratt SC, DeNardo DF. Hydration state does not affect selected body temperature during gravidity or gravidity duration in pythons (Antaresia childreni). Comp Biochem Physiol A Mol Integr Physiol 2024; 293:111624. [PMID: 38462029 DOI: 10.1016/j.cbpa.2024.111624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 03/05/2024] [Accepted: 03/07/2024] [Indexed: 03/12/2024]
Abstract
The embryonic development of many ectothermic species are highly sensitive to temperature and typically have a higher thermal optima than do most other physiological processes. Thus, female ectotherms often maintain a higher and more carefully controlled body temperature when she is supporting developing embryos (early development in oviparous species, throughout development in viviparous species). Considering the positive correlation between body temperature and evaporative water loss, this response could potentially exacerbate female water imbalance in water-limited environments, suggesting that female water balance and egg development may be in conflict. Using Children's pythons (Antaresia childreni), we hypothesized that water deprivation reduces thermophily during gravidity. We split reproductive females into two thermal treatments: those provided with a continuously available thermal gradient of 25-45 °C and those kept at a constant 31 °C. We also had seven non-reproductive females that were provided a thermal gradient. Within each thermal treatment group, we alternatingly assigned females to either have or not have water throughout gravidity. We found that reproduction increased female body temperature, but this increase was not affected by water regime. Reproduction also increased plasma osmolality, and lack of water during gravidity exacerbated this effect. We also found that thermal treatment, but not water regime, significantly influenced gravidity duration, with females given a thermogradient having a shorter gravidity duration, likely as a result of having a higher average body temperature than did the females provided constant heat. Finally, we found that females provided water throughout gravidity had greater clutch masses than did females without water. Further research is needed to improve scientific understanding of the interactions among water balance, body temperature, and various physiological performances.
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Affiliation(s)
- Jill L Azzolini
- School of Life Sciences, Arizona State University, Tempe, AZ 85281-4501, USA.
| | - Stephen C Pratt
- School of Life Sciences, Arizona State University, Tempe, AZ 85281-4501, USA
| | - Dale F DeNardo
- School of Life Sciences, Arizona State University, Tempe, AZ 85281-4501, USA
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2
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Rosso AA, Casement B, Chung AK, Curlis JD, Folfas E, Gallegos MA, Neel LK, Nicholson DJ, Williams CE, McMillan WO, Logan ML, Cox CL. Plasticity of Gene Expression and Thermal Tolerance: Implications for Climate Change Vulnerability in a Tropical Forest Lizard. ECOLOGICAL AND EVOLUTIONARY PHYSIOLOGY 2024; 97:81-96. [PMID: 38728692 DOI: 10.1086/729927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2024]
Abstract
AbstractTropical ectotherms are thought to be especially vulnerable to climate change because they have evolved in temporally stable thermal environments and therefore have decreased tolerance for thermal variability. Thus, they are expected to have narrow thermal tolerance ranges, live close to their upper thermal tolerance limits, and have decreased thermal acclimation capacity. Although models often predict that tropical forest ectotherms are especially vulnerable to rapid environmental shifts, these models rarely include the potential for plasticity of relevant traits. We measured phenotypic plasticity of thermal tolerance and thermal preference as well as multitissue transcriptome plasticity in response to warmer temperatures in a species that previous work has suggested is highly vulnerable to climate warming, the Panamanian slender anole lizard (Anolis apletophallus). We found that many genes, including heat shock proteins, were differentially expressed across tissues in response to short-term warming. Under long-term warming, the voluntary thermal maxima of lizards also increased, although thermal preference exhibited only limited plasticity. Using these data, we modeled changes in the activity time of slender anoles through the end of the century under climate change and found that plasticity should delay declines in activity time by at least two decades. Our results suggest that slender anoles, and possibly other tropical ectotherms, can alter the expression of genes and phenotypes when responding to shifting environmental temperatures and that plasticity should be considered when predicting the future of organisms under a changing climate.
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Bai X, Wang XJ, Ma CS, Ma G. Heat-avoidance behavior associates with thermal sensitivity rather than tolerance in aphid assemblages. J Therm Biol 2023; 114:103550. [PMID: 37344023 DOI: 10.1016/j.jtherbio.2023.103550] [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: 11/30/2022] [Revised: 03/20/2023] [Accepted: 03/21/2023] [Indexed: 06/23/2023]
Abstract
How to predict animals' heat-avoidance behaviors is critical since behavior stands the first line for animals dealing with frequent heat events under ongoing climate warming. However, the discrepancy between the scarcity of research on heat-avoidance behaviors and the commonness of eco-physiological data for thermal tolerance and for thermal sensitivity such as the temperature-dependent survival time makes it difficult to link physiological thermal traits to heat-avoidance behavior. Aphids usually suck plant sap on a fixed site on the host plants at moderate temperatures, but they will leave and seek cooler feeding sites under stressful temperatures. Here we take the cereal aphid assemblages comprising different species with various development stages as a model system. We tested the hypotheses that heat tolerance (critical thermal maximum, CTmax) or heat sensitivity (temperature-dependent declining rate of survival time, similarly hereinafter) would associate with the temperature at which aphid activate heat-avoidance behavior. Specifically, we hypothesized the aphids with less heat tolerance or greater heat sensitivity would take a lower heat risk by leaving the host plant earlier. By mimicking the linear increase in ambient temperature during the daytime, we measured the CTmax and the heat-avoidance temperature (HAT, at which aphids leave the host plant to find cooler places) to understand their heat tolerance and heat-avoidance behavior. Then, we tested the survival time of aphids at different temperatures and calculated the slope of survival time declining with temperature to assess their heat sensitivity (HS). Finally, we examined the relationships between CTmax and HAT and between HS and HAT to understand if the heat-avoidance behavior associates with heat tolerance or with heat sensitivity. The results showed that HS and HAT had a strong correlation, with more heat sensitive individuals displayed lower HAT. By contrast, CTmax and HAT had a weak correlation. Our results thus provide evidence that heat sensitivity is a more reliable indicator than thermal tolerance linking with the heat-avoidance behavior in the aphid assemblages. Most existing studies use the indexes related to thermal tolerance to predict warming impacts. Our findings highlight the urgency to incorporate thermal sensitivity when predicting animal responses to climate change.
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Affiliation(s)
- Xue Bai
- Climate Change Biology Research Group, State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Xue-Jing Wang
- Climate Change Biology Research Group, State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China; School of Life Science, Institute of Life Science and Green Development, Hebei University, Baoding, 071002, China
| | - Chun-Sen Ma
- Climate Change Biology Research Group, State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China; School of Life Science, Institute of Life Science and Green Development, Hebei University, Baoding, 071002, China.
| | - Gang Ma
- Climate Change Biology Research Group, State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
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Sustained Drought, but Not Short-Term Warming, Alters the Gut Microbiomes of Wild Anolis Lizards. Appl Environ Microbiol 2022; 88:e0053022. [PMID: 36165625 PMCID: PMC9552597 DOI: 10.1128/aem.00530-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
As rising temperatures threaten biodiversity across the globe, tropical ectotherms are thought to be particularly vulnerable due to their narrow thermal tolerance ranges. Nevertheless, physiology-based models highlighting the vulnerability of tropical organisms rarely consider the contributions of their gut microbiota, even though microbiomes influence numerous host traits, including thermal tolerance. We combined field and lab experiments to understand the response of the slender anole lizard (Anolis apletophallus) gut microbiome to climatic shifts of various magnitude and duration. First, to examine the effects of long-term climate warming in the wild, we transplanted lizards from the mainland Panama to a series of warmer islands in the Panama Canal and compared their gut microbiome compositions after three generations of divergence. Next, we mimicked the effects of a short-term "heat-wave" by using a greenhouse experiment and explored the link between gut microbiome composition and lizard thermal physiology. Finally, we examined variation in gut microbiomes in our mainland population in the years both before and after a naturally occurring drought. Our results suggest that slender anole microbiomes are surprisingly resilient to short-term warming. However, both the taxonomic and predicted functional compositions of the gut microbiome varied by sampling year across all sites, suggesting that the drought may have had a regional effect. We provide evidence that short-term heat waves may not substantially affect the gut microbiota, while more sustained climate anomalies may have effects at broad geographic scales. IMPORTANCE As climate change progresses, it is crucial to understand how animals will respond to shifts in their local environments. One component of this response involves changes in the microbial communities living in and on host organisms. These "microbiomes" can affect many processes that contribute to host health and survival, yet few studies have measured changes in the microbiomes of wild organisms experiencing novel climatic conditions. We examined the effects of shifting climates on the gut microbiome of the slender anole lizard (Anolis apletophallus) by using a combination of field and laboratory studies, including transplants to warm islands in the Panama Canal. We found that slender anole microbiomes remain stable in response to short-term warming but may be sensitive to sustained climate anomalies, such as droughts. We discuss the significance of these findings for a species that is considered highly vulnerable to climate change.
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Telemeco RS, Gangloff EJ, Cordero GA, Rodgers EM, Aubret F. From performance curves to performance surfaces: Interactive effects of temperature and oxygen availability on aerobic and anaerobic performance in the common wall lizard. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rory S. Telemeco
- Department of Biology California State University Fresno Fresno CA USA
| | - Eric J. Gangloff
- Department of Biological Sciences Ohio Wesleyan University Delaware OH USA
| | - G. Antonio Cordero
- Centre for Ecology, Evolution and Environmental Changes, Department of Animal Biology University of Lisbon Lisbon Portugal
| | - Essie M. Rodgers
- School of Biological Sciences, University of Canterbury Christchurch New Zealand
| | - Fabien Aubret
- Station d’Ecologie Théorique et Expérimentale du CNRS – UPR 2001 Moulis France
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6
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Dufour PC, Tsang TPN, Clusella-Trullas S, Bonebrake TC. No consistent effect of daytime versus night-time measurement of thermal tolerance in nocturnal and diurnal lizards. CONSERVATION PHYSIOLOGY 2022; 10:coac020. [PMID: 35492412 PMCID: PMC9040285 DOI: 10.1093/conphys/coac020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 03/12/2022] [Accepted: 03/17/2022] [Indexed: 06/14/2023]
Abstract
While essential in understanding impacts of climate change for organisms, diel variation remains an understudied component of temporal variation in thermal tolerance limits [i.e. the critical thermal minimum (CTmin) and maximum (CTmax)]. For example, a higher Ctmax might be expected for an individual if the measurement is taken during the day (when heat stress is most likely to occur) instead of at night. We measured thermal tolerance (Ctmin and Ctmax) during both the daytime and night-time in 101 nocturnal and diurnal geckos and skinks in Hong Kong and in South Africa, representing six species and covering a range of habitats. We found that period of measurement (day vs. night) only affected Ctmin in South Africa (but not in Hong Kong) and that Ctmax was unaffected. Body size and species were important factors for determining Ctmax in Hong Kong and Ctmin in South Africa, respectively. Overall, however, we did not find consistent diel variation of thermal tolerance and suggest that measurements of critical thermal limits may be influenced by timing of measurement-but that such effects, when present, are likely to be context-dependent.
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Affiliation(s)
- Pauline C Dufour
- Area of Ecology & Biodiversity, School of Biological Sciences, Kadoorie Biological Sciences Building, The University of Hong Kong, Pok Fu Lam Road, Hong Kong Special Administrative Region, China
| | - Toby P N Tsang
- Area of Ecology & Biodiversity, School of Biological Sciences, Kadoorie Biological Sciences Building, The University of Hong Kong, Pok Fu Lam Road, Hong Kong Special Administrative Region, China
| | - Susana Clusella-Trullas
- Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa
| | - Timothy C Bonebrake
- Corresponding author: Area of Ecology & Biodiversity, School of Biological Sciences, The University of Hong Kong, Hong Kong Special Administrative Region, China.
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Virens E, Cree A. Wind of change: A diurnal skink thermoregulates between cooler set-points and for an increased amount of time in the presence of wind. J Exp Biol 2022; 225:274435. [PMID: 35179605 PMCID: PMC9001919 DOI: 10.1242/jeb.244038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 02/14/2022] [Indexed: 11/20/2022]
Abstract
Wind has the potential to dramatically alter the thermal landscape of habitats, and consequently to affect how ectotherms thermoregulate. However, few studies have directly assessed if wind alters thermoregulation by ectotherms. We compared the thermoregulation of a heliothermic, New Zealand skink under three treatments: no wind, wind at 2 m/s and wind at 6 m/s. We provided captive skinks with housing in which their preferred body temperature was only achievable inside a wind tunnel. During experimental treatments with wind, airflow was generated through the wind tunnel while the maximum available operative temperature remained consistent among treatments. Skinks were able to move in and out of the wind tunnel. Using thermal bio-loggers, we recorded near-continuous skin temperatures of skinks over 90 min. Contrary to our expectations, more skinks tended to thermoregulate in the two wind treatments compared to the treatments without wind (P=0.062) and of the skinks that did thermoregulate, those in the two wind treatments thermoregulated for significantly longer than those in the treatment without wind. The set-point temperatures that skinks thermoregulated between became significantly cooler as windspeed increased, despite skinks having access to the same operative temperatures. Overall, our study suggests that wind has the potential to significantly change the temperatures selected by lizards, even when comparable temperatures are available; wind is therefore an important environmental parameter to consider when studying the thermal ecology of ectotherms, including in the context of climate change.
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Affiliation(s)
- Evelyn Virens
- Department of Zoology, University of Otago, PO Box 56, Dunedin 9054, Aotearoa, New Zealand
| | - Alison Cree
- Department of Zoology, University of Otago, PO Box 56, Dunedin 9054, Aotearoa, New Zealand
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8
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Beltrán I, Perry C, Degottex F, Whiting MJ. Behavioral Thermoregulation by Mothers Protects Offspring from Global Warming but at a Cost. Physiol Biochem Zool 2021; 94:302-318. [PMID: 34260339 DOI: 10.1086/715976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractThermal conditions during embryonic development affect offspring phenotype in ectotherms. Therefore, rising environmental temperatures can have important consequences for an individual's fitness. Nonetheless, females have some capacity to compensate for potential negative consequences that adverse developmental environments may have on their offspring. Recent studies show that oviparous reptiles exhibit behavioral plasticity in nest site selection, which can buffer their embryos against high incubation temperatures; however, much less is known about these responses in viviparous reptiles. We subjected pregnant viviparous skinks, Saiphos equalis, to current or projected midcentury (2050) temperatures to test (i) how elevated temperatures affect female thermoregulatory and foraging behavior; (ii) whether temperatures experienced by females during pregnancy negatively affect the morphology, performance, and behavior of hatchlings; and (iii) whether behavioral thermoregulation during pregnancy is costly to females. Females from the elevated temperature treatment compensated by going deeper belowground to seek cooler temperatures and eating less, and they consequently had a lower body mass relative to snout-to-vent length (condition estimator) compared with females from the current thermal treatment. The temperatures experienced by females in the elevated temperature treatment were high enough to affect foraging and locomotor performance but not the morphology and growth rate of hatchlings. By seeking cooler temperatures, mothers can mitigate some of the effects of high temperatures on their offspring (e.g., reduced body size and growth). However, this protective behavior of females may come at an energetic cost to them. This study adds to growing evidence of lizards' vulnerability to global warming, particularly during reproduction when females are already paying a substantial cost.
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9
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Auer SK, Agreda E, Chen AH, Irshad M, Solowey J. Late-stage pregnancy reduces upper thermal tolerance in a live-bearing fish. J Therm Biol 2021; 99:103022. [PMID: 34420649 DOI: 10.1016/j.jtherbio.2021.103022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 04/23/2021] [Accepted: 05/30/2021] [Indexed: 10/21/2022]
Abstract
Upper thermal limits are considered a key determinant of a population's ability to persist in the face of extreme heat events. However, these limits differ considerably among individuals within a population, and the mechanisms underlying this differential sensitivity are not well understood. Upper thermal tolerance in aquatic ectotherms is thought to be determined by a mismatch between oxygen supply and the increased metabolic demands associated with warmer waters. As such, tolerance is expected to decline during reproduction given the heightened oxygen demand for gamete production and maintenance. Among live-bearing species, upper thermal tolerance of reproductive adults may decline even further after fertilization due to the cost of meeting the increasing oxygen demands of developing embryos. We examined the upper thermal tolerance of live-bearing female Trinidadian guppies at different stages of reproduction and found that critical thermal maximum was similar during the egg yolking and early embryos stage but then declined by almost 0.5 °C during late pregnancy when oxygen demands are the greatest. These results are consistent with the hypothesis that oxygen limitation sets thermal limits and show that reproduction is associated with a decline in upper thermal tolerance.
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10
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Aguado S, Clusella-Trullas S. Intra-specific variation of thermal performance, skin reflectance and body size partially co-vary with climate in a lizard. Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blab049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Thermal adaptation theory posits that variation of thermal traits such as those affecting thermal budgets and the performance of ectotherms should be associated with climate gradients. Under a simple scenario, thermal traits should also co-vary to shape optimal thermal phenotypes under a particular climate. However, geographical variation and covariation of thermal traits can result from other sources of selection and a wide range of other mechanisms. Here, we explore variation and covariation of skin reflectance (melanization), body size and thermal performance traits among three populations of the lizard Cordylus cordylus, a species endemic to South Africa. We also examine relationships between skin reflectance and substrate reflectance, body size and crevice size to test alternative hypotheses. We found partial support for predictions of thermal adaptation to climate regimes for body size, melanization and chill-coma recovery time. Darker lizards also performed optimally at higher temperatures than lighter coloured lizards but there was limited individual covariation between morphological and performance traits. Despite partial support for thermal adaptation, the complex interactions between sex and body size and between substrate reflectance and size underlying skin reflectance emphasized the importance of testing multiple hypotheses when exploring drivers of thermal trait variation within species.
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Affiliation(s)
- Sara Aguado
- Departamento de Biología de Organismos y Sistemas, Universidad de Oviedo, and Unidad Mixta de Investigación en Biodiversidad (UMIB, CSIC-UO-PA), Oviedo, Spain
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11
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Claunch NM, Goodman C, Reed RN, Guralnick R, Romagosa CM, Taylor EN. Invaders from islands: thermal matching, potential or flexibility? Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blab103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Native-range thermal constraints may not reflect the geographical distributions of species introduced from native island ranges in part due to rapid physiological adaptation in species introduced to new environments. Correlative ecological niche models may thus underestimate potential invasive distributions of species from islands. The northern curly-tailed lizard (Leiocephalus carinatus) is established in Florida, including populations north of its native range. Competing hypotheses may explain this distribution: Thermal Matching (distribution reflects thermal conditions of the native range), Thermal Potential (species tolerates thermal extremes absent in the native range) and/or Thermal Flexibility (thermal tolerance reflects local thermal extremes). We rejected the Thermal Matching hypothesis by comparing ecological niche models developed from native vs. native plus invasive distributions; L. carinatus exists in areas of low suitability in Florida as predicted by the native-distribution model. We then compared critical thermal limits of L. carinatus from two non-native populations to evaluate the Thermal Potential and Flexibility hypotheses: one matching native range latitudes, and another 160 km north of the native range that experiences more frequent cold weather events. Critical thermal minima in the northern population were lower than in the south, supporting the Thermal Flexibility hypothesis, whereas critical thermal maxima did not differ.
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Affiliation(s)
- Natalie M Claunch
- School of Natural Resources and Environment, University of Florida, Gainesville, FL, USA
| | - Colin Goodman
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, USA
| | - Robert N Reed
- U.S. Geological Survey, Pacific Island Ecosystems Research Center, Hawai’i National Park, HI, USA
| | - Robert Guralnick
- Department of Natural History, Florida Museum of Natural History, University of Florida, Gainesville, FL, USA
| | - Christina M Romagosa
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, USA
| | - Emily N Taylor
- Biological Sciences Department, California Polytechnic State University, San Luis Obispo, CA, USA
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12
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Logan ML, Neel LK, Nicholson DJ, Stokes AJ, Miller CL, Chung AK, Curlis JD, Keegan KM, Rosso AA, Maayan I, Folfas E, Williams CE, Casement B, Gallegos Koyner MA, Padilla Perez DJ, Falvey CH, Alexander SM, Charles KL, Graham ZA, McMillan WO, Losos JB, Cox CL. Sex-specific microhabitat use is associated with sex-biased thermal physiology in Anolis lizards. J Exp Biol 2021; 224:jeb235697. [PMID: 33328289 DOI: 10.1242/jeb.235697] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 12/07/2020] [Indexed: 08/25/2023]
Abstract
If fitness optima for a given trait differ between males and females in a population, sexual dimorphism may evolve. Sex-biased trait variation may affect patterns of habitat use, and if the microhabitats used by each sex have dissimilar microclimates, this can drive sex-specific selection on thermal physiology. Nevertheless, tests of differences between the sexes in thermal physiology are uncommon, and studies linking these differences to microhabitat use or behavior are even rarer. We examined microhabitat use and thermal physiology in two ectothermic congeners that are ecologically similar but differ in their degree of sexual size dimorphism. Brown anoles (Anolis sagrei) exhibit male-biased sexual size dimorphism and live in thermally heterogeneous habitats, whereas slender anoles (Anolis apletophallus) are sexually monomorphic in body size and live in thermally homogeneous habitats. We hypothesized that differences in habitat use between the sexes would drive sexual divergence in thermal physiology in brown anoles, but not slender anoles, because male and female brown anoles may be exposed to divergent microclimates. We found that male and female brown anoles, but not slender anoles, used perches with different thermal characteristics and were sexually dimorphic in thermal tolerance traits. However, field-active body temperatures and behavior in a laboratory thermal arena did not differ between females and males in either species. Our results suggest that sexual dimorphism in thermal physiology can arise from phenotypic plasticity or sex-specific selection on traits that are linked to thermal tolerance, rather than from direct effects of thermal environments experienced by males and females.
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Affiliation(s)
- Michael L Logan
- Department of Biology, University of Nevada, Reno, NV 89557, USA
- Smithsonian Tropical Research Institute, Panamá City, Panamá
| | - Lauren K Neel
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Daniel J Nicholson
- School of Biological and Chemical Sciences, Queen Mary University, London, E1 4NS, UK
- Zoological Society of London, London, NW1 4RY, UK
| | - Andrew J Stokes
- Department of Environmental Studies, University of Illinois Springfield, Springfield, IL 62703, USA
| | - Christina L Miller
- Department of Biological Sciences, University of Queensland, Queensland, Australia
| | - Albert K Chung
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA
- Department of Biology, Georgia Southern University, Statesboro, GA 30460, USA
| | - John David Curlis
- Department of Biology, Georgia Southern University, Statesboro, GA 30460, USA
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Kaitlin M Keegan
- Department of Geological Sciences and Engineering, University of Nevada, Reno, NV 89557, USA
| | - Adam A Rosso
- Department of Biology, Georgia Southern University, Statesboro, GA 30460, USA
| | - Inbar Maayan
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Edite Folfas
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada, M5S 3B2
| | - Claire E Williams
- Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Brianna Casement
- Department of Biology and Environmental Science, Heidelberg University, Tiffin, OH 44883, USA
| | - Maria A Gallegos Koyner
- Department of Forest Sciences, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | | | - Cleo H Falvey
- Department of Biology, University of Massachusetts, Boston, MA 02125, USA
| | - Sean M Alexander
- Departement of Biology, Rutgers University, Camden, NJ 08901, USA
| | | | - Zackary A Graham
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - W Owen McMillan
- Smithsonian Tropical Research Institute, Panamá City, Panamá
| | - Jonathan B Losos
- Department of Biology, Washington University, Saint Louis, MO 63130, USA
| | - Christian L Cox
- Department of Biological Sciences and Institute for the Environment, Florida International University, FL 33199, USA
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Evidence from Tarentola mauritanica (Gekkota: Phyllodactylidae) helps validate thermography as a tool to infer internal body temperatures of lizards. J Therm Biol 2020; 93:102700. [PMID: 33077121 DOI: 10.1016/j.jtherbio.2020.102700] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 07/30/2020] [Accepted: 08/03/2020] [Indexed: 11/20/2022]
Abstract
Infrared (IR) thermal imaging has become an increasingly popular tool to measure body temperature of animals. The high-resolution data it provides with short lag and minimum disturbance makes it an appealing tool when studying reptile thermal ecology. However, due to the common phenomenon of regional heterothermy and surface-to-core temperature gradients, it is essential to select the appropriate body part to measure and provide calibrations to accurately infer internal body temperatures. This work follows from a previous study on lacertid lizards to assess the reliability of thermography-measured body temperatures, from several body locations, as a proxy for internal body temperature in lizards. This study focuses on the Moorish gecko, Tarentola mauritanica, due to its distant phylogenetic relationship and its different ecology and morphology from the previously tested species. A total of 60 adult geckos of both sexes and of a range of sizes were tested in thermal gradients and subjected to a sequence of randomly assorted treatments of heating and cooling. The temperatures of the animals were periodically measured with a thermal camera at six different body parts and, immediately after, the cloacal temperature was then measured with a thermocouple probe. Body parts' temperatures, obtained thermographically, were regressed against cloacal temperature using OLS regression and the pairwise correlations were tested using Spearman coefficients. Relationships among all body parts and between all body parts and the cloaca were strong in all cases (R2 > 0.87, Spearman Correlation > 0.95). The observed pattern was very similar to those previously obtained from lacertid lizards. Ultimately, the eye proved to provide the best overall proxy for internal temperature, when accounting for both the slope and intercept of the regression. Hence, this study provides further support for the establishment of the eye as the standard location to infer internal body temperatures of lizards through thermography.
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Chukwuka CO, Monks JM, Cree A. Heat and water loss versus shelter: a dilemma in thermoregulatory decision making for a retreat-dwelling nocturnal gecko. J Exp Biol 2020; 223:jeb231241. [PMID: 32778565 DOI: 10.1242/jeb.231241] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 08/02/2020] [Indexed: 08/26/2023]
Abstract
Understanding the interaction between upper voluntary thermal limit (VTmax) and water loss may aid in predicting responses of ectotherms to increasing temperatures within microhabitats. However, the temperature at which climate heating will force cool-climate nocturnal lizards to abandon daytime retreats remains poorly understood. Here, we developed a new laboratory protocol for determining VTmax in the retreat-dwelling, viviparous Woodworthia 'Otago/Southland' gecko, based on escape behaviour (abandonment of heated retreat). We compared the body temperature (Tb) at VTmax, and duration of heating, between two source groups with different thermal histories, and among three reproductive groups. We also examined continuous changes in Tb (via an attached biologger) and total evaporative water loss (EWL) during heating. In the field, we measured Tb and microhabitat thermal profiles to establish whether geckos reach VTmax in nature. We found that VTmax and duration of heating varied between source groups (and thus potentially with prior thermal experience), but not among reproductive groups. Moreover, geckos reached a peak temperature slightly higher than VTmax before abandoning the retreat. Total EWL increased with increasing VTmax and with the duration of heating. In the field, pregnant geckos with attached biologgers reached VTmax temperature, and temperatures of some separately monitored microhabitats exceeded VTmax in hot weather implying that some retreats must be abandoned to avoid overheating. Our results suggest that cool-climate nocturnal lizards that inhabit daytime retreats may abandon retreats more frequently if climate warming persists, implying a trade-off between retention of originally occupied shelter and ongoing water loss due to overheating.
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Affiliation(s)
- Christian O Chukwuka
- Department of Zoology, University of Otago, Dunedin 9016, New Zealand
- Department of Biology, Alex Ekwueme Federal University, Ndufu-Alike Ikwo, Abakaliki, Ebonyi State, Nigeria
| | - Joanne M Monks
- Department of Zoology, University of Otago, Dunedin 9016, New Zealand
- Department of Conservation, Dunedin 9058, New Zealand
| | - Alison Cree
- Department of Zoology, University of Otago, Dunedin 9016, New Zealand
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Bodensteiner BL, Agudelo‐Cantero GA, Arietta AZA, Gunderson AR, Muñoz MM, Refsnider JM, Gangloff EJ. Thermal adaptation revisited: How conserved are thermal traits of reptiles and amphibians? JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2020; 335:173-194. [DOI: 10.1002/jez.2414] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 07/17/2020] [Accepted: 09/04/2020] [Indexed: 12/31/2022]
Affiliation(s)
- Brooke L. Bodensteiner
- Department of Ecology and Evolutionary Biology Yale University New Haven Connecticut USA
| | - Gustavo A. Agudelo‐Cantero
- Department of Physiology, Institute of Biosciences University of São Paulo São Paulo Brazil
- Department of Biology ‐ Genetics, Ecology, and Evolution Aarhus University Aarhus Denmark
| | | | - Alex R. Gunderson
- Department of Ecology and Evolutionary Biology Tulane University New Orleans Louisiana USA
| | - Martha M. Muñoz
- Department of Ecology and Evolutionary Biology Yale University New Haven Connecticut USA
| | | | - Eric J. Gangloff
- Department of Zoology Ohio Wesleyan University Delaware Ohio USA
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16
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Taylor EN, Diele‐Viegas LM, Gangloff EJ, Hall JM, Halpern B, Massey MD, Rödder D, Rollinson N, Spears S, Sun B, Telemeco RS. The thermal ecology and physiology of reptiles and amphibians: A user's guide. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2020; 335:13-44. [DOI: 10.1002/jez.2396] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 06/12/2020] [Accepted: 06/13/2020] [Indexed: 02/05/2023]
Affiliation(s)
- Emily N. Taylor
- Biological Sciences Department California Polytechnic State University San Luis Obispo California
| | | | | | - Joshua M. Hall
- Department of Biological Sciences Auburn University Auburn Alabama
| | | | - Melanie D. Massey
- Department of Biology Dalhousie University Halifax Nova Scotia Canada
| | - Dennis Rödder
- Zoologisches Forschungsmuseum Alexander Koenig Bonn Germany
| | - Njal Rollinson
- Department of Ecology and Evolutionary Biology University of Toronto St. Toronto Ontario Canada
- School of the Environment University of Toronto Toronto Ontario Canada
| | - Sierra Spears
- Department of Zoology Ohio Wesleyan University Delaware Ohio
| | - Bao‐jun Sun
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology Chinese Academy of Sciences Beijing China
| | - Rory S. Telemeco
- Department of Biology California State University Fresno California
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