The effect of temperature on the metabolism of juvenile tuatara,<i>Sphenodon punctatus</i>

Cartland, L. K.; Grimmond, N. M.

doi:10.1080/03014223.1994.9518006

Cited by 17 publications

(9 citation statements)

References 21 publications

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“…Our observations are consistent with those of Cartland & Grimmond (1994) and Blair et al (2000) on the oxygen consumption rates of juvenile tuatara at 20°C and with those of Thompson & Daugherty (1998) on the effect of body mass on oxygen consumption rate.…”

Section: Discussionsupporting

confidence: 82%

“…The circadian rhythms in metabolic rate observed suggest that studies of metabolic rate in tuatara and other reptiles have often included an unrecognised but significant source of variation in their results. For example, the time of day at which we observed major diel changes in oxygen consumption rate (factorial change of 2.2) in tuatara included the typical time period in which measurements have been made previously in this species (e.g., by Cartland & Grimmond 1994;Blair et al 2000). We strongly agree with recent comments (Zaiden 2003; Roe et al 2004;Winne & Keck 2004) on the importance of reporting time of measurements and analyses of the temporal changes in behaviour and metabolism in reptiles.…”

Section: Discussionsupporting

confidence: 70%

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A circadian rhythm in oxygen consumption rate in juvenile tuatara(Sphenodon punctatus)

Birchard¹,

Nelson²,

Daugherty³

2006

New Zealand Journal of Zoology

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Tuatara have been given a high conservation priority because of their unique taxonomic status and limited distribution. Significant additional information on their biology is needed to maximise the chances of successful long-term management. The metabolic rate of 12 juvenile tuatara was measured as oxygen consumption (mlh -1 ) over the daily cycle under constant light conditions. It showed a circadian rhythm, with peak rates from midday until midnight and a nadir in late morning (1100-1200 h). These results are consistent with juveniles having a late-afternoon to nocturnal activity pattern similar to that of adults. These results support accounts of temporal variation in behaviour and physiological rates in reptilian species, which have significant implications for understanding the physiology and energetics of reptiles generally.

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Section: Discussionsupporting

confidence: 82%

Section: Discussionsupporting

confidence: 70%

A circadian rhythm in oxygen consumption rate in juvenile tuatara(Sphenodon punctatus)

Birchard¹,

Nelson²,

Daugherty³

2006

New Zealand Journal of Zoology

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“…The thermal sensitivity of physiological performances has received little attention in tuatara, so it is diYcult to know if a 1.3°C diVerence in T b has ecological signiWcance. Metabolic rate in tuatara increases with T b between 5 and 15°C but tends to plateau between 15 and 20°C (Wells et al 1990;Cartland and Grimmond 1994), as T sel is approached. Thus, a 1.3°C diVerence in T b between 16.4 and 17.7°C may not have had a large eVect on physiological performances of tuatara (this would not have been true, however, for a T b below 15°C or close to the lower or upper thermal tolerance of the species).…”

Section: Discussionmentioning

confidence: 94%

A cold-adapted reptile becomes a more effective thermoregulator in a thermally challenging environment

Besson

Cree

2010

Oecologia

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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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“…Resting metabolic rate of juvenile tuatara is significantly affected by ambient temperature (Cartland & Grimmond, 1994). Temperature affects readiness to feed, gut passage time and digestive efficiency in cold-adapted New Zealand lizards (Lawrence, 1997).…”

Section: Adaptive Significance Of Tsd For Tuataramentioning

confidence: 99%

Egg mass determines hatchling size, and incubation temperature influences post‐hatching growth, of tuatara Sphenodon punctatus

et al. 2004

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The size of reptile hatchlings can be phenotypically plastic in response to incubation temperature, and size is a trait likely to influence fitness -i.e. hatchling size is proposed as an indicator of quality. The parental and incubation temperature effects on the size of one of New Zealand's most biologically significant reptile species, the tuatara Sphenodon punctatus are investigated. Artificial incubation at constant temperatures is used to produce founders for new captive and wild populations of tuatara and to augment existing rare populations. We compare size of hatchling tuatara from artificial and natural incubation treatments. The relationship of hatchling size with incubation temperature and sex is examined, and we investigate whether our results support differential fitness models for the evolution of temperature-dependent sex determination in tuatara. Initial egg mass is the most important factor affecting size of hatchling tuatara and is still an important influence at 10 months of age. Incubation temperature does not greatly influence size of hatchlings, but significantly influences size by 10 months of age. Constant artificial incubation conditions result in larger, but possibly less aggressive, juveniles than those from more variable natural incubation conditions by 10 months of age. Evidence from size patterns of tuatara incubated in natural nests supports differential fitness models for the adaptive significance of temperature-dependent sex determination. Thermal variation has little effect on size of male hatchlings, but female embryos that develop in more stable thermal conditions, in more reliable sites for hatching, are bigger and have longer jaws.

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The effect of temperature on the metabolism of juvenile tuatara,Sphenodon punctatus

Cited by 17 publications

References 21 publications

A circadian rhythm in oxygen consumption rate in juvenile tuatara(Sphenodon punctatus)

A circadian rhythm in oxygen consumption rate in juvenile tuatara(Sphenodon punctatus)

A cold-adapted reptile becomes a more effective thermoregulator in a thermally challenging environment

Egg mass determines hatchling size, and incubation temperature influences post‐hatching growth, of tuatara Sphenodon punctatus

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