Licht-im-Terrarium: Literaturdatenbank
Licht-im-Terrarium: Literaturdatenbank |
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Firth, B. T., Thompson, M. B., Kennaway, D. J., & Belan, I. (1999). Thermal sensitivity of reptilian melatonin rhythms: "cold" tuatara vs. "warm" skink. American Journal of Physiology, 277(6), R1620–R1626. Added by: Sarina (2009-08-24 16:41:01) |
| Resource type: Journal Article BibTeX citation key: Firth1999 View all bibliographic details  |
Categories: Englisch = English Keywords: Chronobiologie = Chronobiology, Echsen = Lizards, Reptilien = Reptiles Creators: Belan, Firth, Kennaway, Thompson Collection: American Journal of Physiology |
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| Abstract |
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Daily rhythms in plasma melatonin levels were compared in two ecologically diverse reptilian species under natural environmental conditions in autumn. The nocturnal, cold temperature-adapted tuatara (Sphenodon punctatus) had a melatonin rhythm of much lower amplitude than did the diurnal desert-adapted sleepy lizard (Tiliqua rugosa). Experiments in controlled laboratory environments showed that, although both species are capable of attaining a comparable melatonin peak (approximately 750 pmol/l), the threshold temperature at which a significant daily rhythm occurs is approximately 15 degrees C in S. punctatus compared with approximately 25 degrees C in T. rugosa. This difference probably reflects the disparate thermoregulatory adaptations of the two species, S. punctatus favoring mean activity temperatures of 11.5 degrees C and T. rugosa, 32.5 degrees C. In ectotherms such as reptiles, therefore, species-typical thermoregulatory behavior may provide thermal cues that interact with photoperiod to provide the appropriate melatonin signal for the regulation of annual physiological cycles.
Added by: Sarina |