Social Behavior of the Tuatara, Sphenodon punctatus

Gillingham, James C.; Carmichael, Christopher; Miller, Tracy J.

doi:10.2307/1466993

Cited by 52 publications

(74 citation statements)

References 14 publications

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“…In addition, wild tuatara forage mainly at night, so there is no major conXict, during the day, between foraging and thermoregulation. On the other hand, adult tuatara also engage in defensive and mating behaviour during the day through the mating season (Gillingham et al 1995), so environments with more limited thermoregulation might limit these behaviours. The line between nocturnality and diurnality in some species can sometimes be blurred (indeed, tuatara have sometimes been described as "diurno-nocturnal"; Werner and Whitaker 1978).…”

Section: Discussionmentioning

confidence: 99%

“…Tuatara are primarily nocturnal, in that they roam most widely from their burrows and forage mainly at night, especially on warm nights when air temperatures reach up to 20°C (Walls 1983). However, tuatara are also partly diurnal; they feed during the day when an opportunity arises (Walls 1981), engage in defensive and mating behaviour during the day through the mating season (Gillingham et al 1995) and bask at the entrance of their burrows in the morning (Barwick 1982). Basking tuatara reach T b s of 25-26°C or even 30.1°C (Barwick 1982).…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Besson

Cree

2010

Oecologia

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“…Tuatara have a seasonally monogamous mating system with low levels of polyandry and polygyny, but do not exhibit long-term pair bonding or parental care (Moore 2008). Tuatara are sexually dimorphic, and mating involves a conspicuous courtship ritual followed by copulation (Gillingham et al 1995;Moore 2008). Both mate choice and male-male competition may be important factors in the mating system of tuatara.…”

Section: Introductionmentioning

confidence: 99%

Influence of major histocompatibility complex genotype on mating success in a free-ranging reptile population

et al. 2009

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Major histocompatibility complex (MHC) genes are highly polymorphic components of the vertebrate immune system, which play a key role in pathogen resistance. MHC genes may also function as odourrelated cues for mate choice, thus ensuring optimal MHC diversity in offspring. MHC-associated mate choice has been demonstrated in some fish, bird and mammal species but it is not known whether this is a general vertebrate phenomenon. We investigated whether MHC-associated mate choice occurs in a wild population of tuatara (Sphenodon punctatus), a territorial and sexually dimorphic reptile. We found weak evidence for MHC-disassortative mating, based on amino acid genotypic distance between pairs, when mated pairs were directly compared with potential pairs in close spatial proximity. No significant association was found between male mating success, number of MHC sequences, microsatellite heterozygosity or MHC lineage. The major determinant of mating success in tuatara was male body size, which was not related to MHC lineage or microsatellite heterozygosity. Our results suggest that male competitive ability is the primary driver of mating success in tuatara. However, MHC-associated preferences also appear to play a role, possibly as a kin avoidance mechanism during territory formation.

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“…In both habitats, tuatara exhibit high territory fidelity and the adult spatial structure is relatively static over time (Moore 2008). Tuatara are nocturnal in the pastures, but they are active throughout the day and night in the forest (Gillingham et al . 1995).…”

Section: Introductionmentioning

confidence: 99%

Fine‐scale genetic structure of a long‐lived reptile reflects recent habitat modification

et al. 2008

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Anthropogenic habitat fragmentation--ubiquitous in modern ecosystems--has strong impacts on gene flow and genetic population structure. Reptiles may be particularly susceptible to the effects of fragmentation because of their extreme sensitivity to environmental conditions and limited dispersal. We investigate fine-scale spatial genetic structure, individual relatedness, and sex-biased dispersal in a large population of a long-lived reptile (tuatara, Sphenodon punctatus) on a recently fragmented island. We genotyped individuals from remnant forest, regenerating forest, and grassland pasture sites at seven microsatellite loci and found significant genetic structuring (R(ST)=0.012) across small distances (<500 m). Isolation by distance was not evident, but rather, genetic distance was weakly correlated with habitat similarity. Only individuals in forest fragments were correctly assignable to their site of origin, and individual pairwise relatedness in one fragment was significantly higher than expected. We did not detect sex-biased dispersal, but natural dispersal patterns may be confounded by fragmentation. Assignment tests showed that reforestation appears to have provided refuges for tuatara from disturbed areas. Our results suggest that fine-scale genetic structuring is driven by recent habitat modification and compounded by the sedentary lifestyle of these long-lived reptiles. Extreme longevity, large population size, simple social structure and random dispersal are not strong enough to counteract the genetic structure caused by a sedentary lifestyle. We suspect that fine-scale spatial genetic structuring could occur in any sedentary species with limited dispersal, making them more susceptible to the effects of fragmentation.

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Social Behavior of the Tuatara, Sphenodon punctatus

Cited by 52 publications

References 14 publications

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

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

Influence of major histocompatibility complex genotype on mating success in a free-ranging reptile population

Fine‐scale genetic structure of a long‐lived reptile reflects recent habitat modification

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