Variation of preferred body temperatures along an altitudinal gradient: A multi-species study

Trochet, Audrey; Dupoué, Andréaz; Souchet, Jérémie; Bertrand, Romain; Deluen, Marine; Murarasu, Sophie; Calvez, Olivier; Martinez‐Silvestre, Albert; Verdaguer-Foz, Isabel; Darnet, Elodie; Chevalier, Hugo Le; Mossoll‐Torres, Marc; Guillaume, Olivier; Aubret, Fabien

doi:10.1016/j.jtherbio.2018.08.002

Cited by 34 publications

(32 citation statements)

References 59 publications

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“…previous studies of squamate reptiles, we considered these measures as best estimates of behaviorally selected body temperatures during the activity period of the day in the absence of thermoregulation costs [14,47]. Preferred body temperature (PBT) was calculated as the daily average of body temperatures [48], thermal precision was calculated as the daily standard deviation of body temperatures (low values indicate more precise thermoregulation), and set-point range was calculated from the central 50% of all body temperatures [49]. In addition, we ran a qualitative, pilot study with one climatic chamber where 60 lizards were observed to detect any obvious disturbance caused by the contained environment (noise, electromagnetic disturbance, etc.)…”

Section: Plos Onementioning

confidence: 99%

Short-term changes in air humidity and water availability weakly constrain thermoregulation in a dry-skinned ectotherm

et al. 2021

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Thermoregulation is critical for ectotherms as it allows them to maintain their body temperature close to an optimum for ecological performance. Thermoregulation includes a range of behaviors that aim at regulating body temperature within a range centered around the thermal preference. Thermal preference is typically measured in a thermal gradient in fully-hydrated and post-absorptive animals. Short-term effects of the hydric environment on thermal preferences in such set-ups have been rarely quantified in dry-skinned ectotherms, despite accumulating evidence that dehydration might trade-off with behavioral thermoregulation. Using experiments performed under controlled conditions in climatic chambers, we demonstrate that thermal preferences of a ground-dwelling, actively foraging lizard (Zootoca vivipara) are weakly decreased by a daily restriction in free-standing water availability (less than 0.5°C contrast). The influence of air humidity during the day on thermal preferences depends on time of the day and sex of the lizard, and is generally weaker than those of of free-standing water (less than 1°C contrast). This shows that short-term dehydration can influence, albeit weakly, thermal preferences under some circumstances in this species. Environmental humidity conditions are important methodological factors to consider in the analysis of thermal preferences.

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Section: Plos Onementioning

confidence: 99%

Short-term changes in air humidity and water availability weakly constrain thermoregulation in a dry-skinned ectotherm

et al. 2021

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“…: 8.5±2.9 days) Lizards were offered their first meal after their initial measurement (2 days after capture) and food was withheld for 2 days before each subsequent measure. Each individual was placed in a custom-made 250 ml opaque metabolic chamber, which was then placed in an incubator set at 32°C for 1 h before measurement, a temperature intermediate between thermal preference (32.6°C) and field body temperatures (30.6°C) for gravid females in this area (Trochet et al, 2018;F.A., unpublished data). This acclimation time allows body temperature to equilibrate and reduces effects of handling stress (Braña, 1993;Tosini and Avery, 1996).…”

Section: Maternal Metabolic Ratementioning

confidence: 99%

Transplanting gravid lizards to high elevation alters maternal and embryonic oxygen physiology, but not reproductive success or hatchling phenotype

Kouyoumdjian

Gangloff

Souchet

et al. 2019

Journal of Experimental Biology

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Increased global temperatures have opened previously inhospitable habitats, such as at higher elevations. However, the reduction of oxygen partial pressure with increase in elevation represents an important physiological constraint that may limit colonization of such habitats, even if the thermal niche is appropriate. To test the mechanisms underlying the response to ecologically relevant levels of hypoxia, we performed a translocation experiment with the common wall lizard (Podarcis muralis), a widespread European lizard amenable to establishing populations outside its natural range. We investigated the impacts of hypoxia on the oxygen physiology and reproductive output of gravid common wall lizards and the subsequent development and morphology of their offspring. Lowland females transplanted to high elevations increased their haematocrit and haemoglobin concentration within days and maintained routine metabolism compared with lizards kept at native elevations. However, transplanted lizards suffered from increased reactive oxygen metabolite production near the oviposition date, suggesting a cost of reproduction at high elevation. Transplanted females and females native to different elevations did not differ in reproductive output (clutch size, egg mass, relative clutch mass or embryonic stage at oviposition) or in post-oviposition body condition. Developing embryos reduced heart rates and prolonged incubation times at high elevations within the native range and at extreme high elevations beyond the current range, but this reduced oxygen availability did not affect metabolic rate, hatching success or hatchling size. These results suggest that this opportunistic colonizer is capable of successfully responding to novel environmental constraints in these important life-history stages.

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“…jarrovii , although in the opposite direction than that predicted by Huey & Slatkin’s (1976) cost–benefit model of thermoregulation. Although studies have made comparisons between populations at different latitudes (Ellner & Karasov, 1993; Andrews, 1998) and elevations (Bouazza et al ., 2016; Trochet et al ., 2018; Wu et al ., 2018), the vast majority of studies make comparisons between only two or three populations (e.g. Burns, 1970; Ballinger, 1973; Grant & Dunham, 1990; Diaz, 1997; Olsson & Shine, 2002; Iraeta, Salvador & Díaz, 2013; Diaz de la Vega‐Pérez et al ., 2019; Gilbert & Miles, 2019; Senior et al ., 2019), thus limiting inferential power and representativity.…”

Section: Discussionmentioning

confidence: 99%

Changes in thermal quality of the environment along an elevational gradient affect investment in thermoregulation by Yarrow’s spiny lizards

Lymburner

Blouin‐Demers

2020

Journal of Zoology

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Body temperature affects physiological processes and, consequently, is assumed to have a large impact on fitness. Lizards need to thermoregulate behaviourally to maintain their body temperature within a range that maximizes performance, but there are costs associated with thermoregulation. The thermal quality of an environment directly affects the amount of time and energy that must be invested by an individual to maintain an optimal body temperature for performance; time and energy are major costs of thermoregulation. According to Huey and Slatkin's (Q. Rev. Biol. 1976, 363) cost-benefit model of thermoregulation, lizards should only thermoregulate when the benefits outweigh the costs. Thus, in habitats of poor thermal quality, lizards should invest less into thermoregulation. We tested the hypothesis that the thermal quality of an environment dictates investment in thermoregulation across an elevational gradient. Increases in elevation are accompanied by decreases in temperature and therefore thermal quality. We recorded body temperatures of Yarrow's spiny lizards (Sceloporus jarrovii) at ten talus slopes along an elevational gradient of over 1000 m. We found a significant positive relationship between elevation and effectiveness of thermoregulation, opposite to the prediction of the cost-benefit model of thermoregulation. This suggests that the disadvantages of thermoconformity may be greater than the costs of thermoregulating as habitats become more thermally challenging.

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Variation of preferred body temperatures along an altitudinal gradient: A multi-species study

Cited by 34 publications

References 59 publications

Short-term changes in air humidity and water availability weakly constrain thermoregulation in a dry-skinned ectotherm

Short-term changes in air humidity and water availability weakly constrain thermoregulation in a dry-skinned ectotherm

Transplanting gravid lizards to high elevation alters maternal and embryonic oxygen physiology, but not reproductive success or hatchling phenotype

Changes in thermal quality of the environment along an elevational gradient affect investment in thermoregulation by Yarrow’s spiny lizards

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