Zoologisches Institut der Universität, Poppeldorfer Schloß, D-5300, Bonn 1, Federal Republic of Germany.
Oecologia. 1989 Mar;80(1):32-8. doi: 10.1007/BF00789928. Epub 2013 Mar 13.
The body temperature of free-ranging Andean toadsBufo spinulosus was measured either directly or radiotelemetrically during two 15-day periods at 3200 m elevation in the Mantaro Valley, Central Perú. All toads attempted to maintain their diurnal sum of body temperature within a narrow range. Consequently thermoregulatory behaviour differed according to cloud cover and precipitation. If the sky was clear, toads emerged from their hiding place and exposed themselves to solar radiation during 3-5 h in the morning. Core temperature increased up to 15° C above the air temperature in shade and reached maximum values of about 32° C. At air temperatures (in sun) exceeding 29° C, toads maintained body temperatures below 32° C by evaporative cooling. Following heliothermic heating during the moring toads retreated to the shade, thereby decreasing body temperature below air temperature. Under overcast sky toads remained exposed during the whole day displaying body temperatures at or slightly above ambient levels. Quantitative models to predict the core temperature of toads under the different weather conditions demonstrated that the substrate temperature was the main energy source accounting for 64.6-77.9% of total variance whereas air temperature was of minor importance (1.5-4.4%). The unexplained variance was probably due to evaporative cooling. The volume of urine stored into the urinary bladder of toads varied diurnally; during basking in the morning hours most bladders contained large volumes of urine, whereas during the afternoon the bladders were mostly empty. The bladder contents probably serve as water reserves during basking when evaporative water loss was high. Toads preferred sites that provided shady hiding places as well as sun-exposed bare soil within a radius of 5 m. However, they frequently changed their centers of activity and moved to other sites in 20-70 m distance after periods of 2-5 days. The helio-and thigmothermic behaviour of the Andean toad permits the maintenance of high core temperature during morning which probably increases the digestion rate and accelerate growth. Evaporative cooling and preference of shady sites were employed to regulate body temperature below the morning levels in response to the constraints of water balance. Periodic changes between thigmothermic behaviour and locomotory activity during the night maintains body temperature above air temperature and prolongs the period of food uptake.
在秘鲁中部 Mantaro 山谷海拔 3200 米处，我们通过直接测量或无线电遥测的方式，在两个为期 15 天的时间段内测量了自由活动的安第斯蟾蜍 Bufo spinulosus 的体温。所有蟾蜍都试图将其白天的体温总和维持在一个狭窄的范围内。因此，其体温调节行为因云量和降水而异。如果天空晴朗，蟾蜍会从藏身之处出来，在上午的 3-5 小时内暴露在太阳辐射下。核心体温比阴凉处的空气温度高出 15°C，达到约 32°C 的最大值。当空气温度（在阳光下）超过 29°C 时，蟾蜍通过蒸发冷却将体温保持在 32°C 以下。上午的太阳加热后，蟾蜍会退到阴凉处，从而使体温低于空气温度。在阴天，蟾蜍整天都暴露在外，体温与环境温度持平或略高。用于预测不同天气条件下蟾蜍核心体温的定量模型表明，基质温度是主要的能量来源，占总方差的 64.6-77.9%，而空气温度则相对不重要（1.5-4.4%）。未解释的方差可能是由于蒸发冷却造成的。蟾蜍储存在膀胱中的尿液量随昼夜变化而变化；在上午的晒太阳时间里，大多数膀胱中都含有大量尿液，而在下午，膀胱大多是空的。膀胱内容物可能在蒸发失水较高的情况下作为沐浴时的水分储备。蟾蜍喜欢有阴凉藏身之处和 5 米半径内暴露在阳光下的裸露土壤的地方。然而，它们经常在 2-5 天后每隔 20-70 米更换活动中心和地点。安第斯蟾蜍的太阳和温度依赖行为允许其在早晨维持较高的核心体温，这可能会提高消化率并加速生长。蒸发冷却和对阴凉地点的偏好被用来将体温调节到早晨水平以下，以应对水平衡的限制。夜间的温度依赖行为和运动活动之间的周期性变化使体温保持在空气温度以上，并延长了进食时间。
