Thermoregulation and activity pattern of the high-mountain lizard Phymaturus palluma (Tropiduridae) in Chile

• Main Authors: Marcela A. Vidal, Evelyn Habit, Pedro Victoriano, Angélica González-Gajardo, Juan C. Ortiz
• Format: Article
• Language: English
• Published: Pensoft Publishers 2010-02-01
• Series: Zoologia (Curitiba)
• Subjects: Age classes; daily activity; sexual dimorphism
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-46702010000100003

Behavioral and physiological mechanisms of thermoregulation in ectotherms are conditioned by thermal constraints. These mechanisms may be even more restrictive when environmental conditions are unfavorable for individuals, especially when sexual dimorphism segregates the sexes spatially. In order to understand behavioral and physiological regulation mechanisms, we investigated the thermal biology of Phymaturus palluma (Molina, 1782), a sexually size dimorphic, high-mountain lizard that inhabits extreme climatic conditions. P. palluma showed a bimodal activity pattern, a major peak in the morning (11:00-13:30h) and in the afternoon (15:30-18:00 h). The lizards were more active when substrate temperatures were between 25 and 28º C. The highest abundance was found around 27º C (between 11:00-12:30). Females showed greater activity than males in the early morning. Sub-adults and juveniles did not show differences in their activity pattern. There was a positive relationship between body temperature and air and substrate temperatures, suggesting typically thigmothermal regulation.