Thermal biology of Amphisbaena munoai (Squamata: Amphisbaenidae)

ABSTRACT Studies on the thermal biology of fossorial reptiles that examine the relationship between the body temperature and thermal environment are needed to determine the extent of their thermoregulation abilities. This study assessed the thermal biology of Amphisbaena munoai Klappenbach, 1969 in the rocky fields of the Rio Grande do Sul and in the laboratory. The body temperature of most individuals was between 24 and 30 °C, both in the field (n = 81) and laboratory (n = 19). More individuals were caught in winter (n = 55) and spring (n = 60) than in summer (n = 25) and fall (n = 45), and in spring, individuals showed similar nocturnal and diurnal activities. In the laboratory, we found individuals with body temperatures up to 5 °C higher than the ambient temperature (n = 4), suggesting that some physiological mechanisms participate in the thermoregulation of these animals. Amphisbaena munoai is a thigmothermic species that is capable of actively regulating its temperature by selecting microhabitats such that its various activities occur within an ideal temperature range. This study is the first to evaluate the effect of seasonality and diurnal and nocturnal variations on the thermoregulation of an amphisbaenid.

摘要 目前亟需开展穴居爬行动物热生物学相关研究，解析其体温与热环境间的关联，以明确其体温调节能力的发挥程度。本研究针对巴西南大河州岩生境中的穆诺阿双足蚓蜥（Amphisbaena munoai Klappenbach, 1969）开展了野外与室内热生物学评估。野外（n=81）与室内（n=19）观测的多数个体体温均处于24~30 ℃区间。冬（n=55）、春（n=60）两季捕获的个体数多于夏（n=25）、秋（n=45）两季；春季时，该物种的昼行与夜行活动频次相近。室内实验中，有4尾个体的体温较环境温度高出最多5 ℃，提示存在某些生理机制参与该物种的体温调节过程。穆诺阿双足蚓蜥属于接触调温型物种，可通过选择适宜微生境主动调控体温，使其各项生命活动维持在理想体温区间内。本研究首次评估了季节节律与昼夜变化对蚓蜥科物种体温调节的影响。