荒漠沙蜥活动期间的体温节律

爬行动物的体温依赖于外界热环境的变化,本研究以荒漠沙蜥(Phrynocephalus przewalskii)为对象,收集其冬眠前活动期间的体温与地面和离地10 cm的空气温度,研究爬行动物体温节律性变化与环境温度的关系.研究结果表明,荒漠沙蜥在环境温度高于20℃后开始外出活动,其体温随着地面温度和空气温度的上升而逐步...     

温度对中国林蛙卵孵化和孵出热耐受性的影响

为了解中国林蛙(Rana chensinensis)卵的孵化率、发育起点温度、发育有效积温、孵化后蝌蚪的成活率和蝌蚪的热耐受性,将当天产出的中国林蛙卵采集回实验室,分别置于5个不同温度(10℃、15℃、20℃、25℃和30℃)下孵化,观察和测量记录卵的孵化率、孵化3d后蝌蚪的成活率、全长及每个温度下卵的发育历期。利用温度梯度装置观察记录孵化10d后蝌蚪的最适温度、逃避温度和致死温度。光照周期设为14L∶10D,湿度设为85%。结果表明,温度对中国林蛙卵的孵化率影响显著;孵化3d后蝌蚪的成活率随着温度的升高而降低,30℃下孵化的蝌蚪在2d之内全部死亡;温度对中国林蛙卵孵化3d后蝌蚪全长的影响极显著,蝌蚪的全长随着温度的升高而增加;应用直线回归法和直接最优化法计算中国林蛙卵的发育起点温度和有效积温,分别为0.51℃、65.29日度和0.38℃、65.52日度,直接最优化法优于直线回归法。经过4个不同温度(10℃、15℃、20℃和25℃)孵化10d后蝌蚪的最适温度分别为(13.2±1.6)℃、(15.7±1.9)℃、(17.3±2.1)℃和(19.5±2.3)℃;逃避温度分别为(28.8±1.4)℃、(30.2±1.6)℃、(31.6±1.3)℃和(33.1±1.8)℃;致死温度分别为(32.9±1.7)℃、(33.8±1.5)℃、(35.2±1.2)℃和(36.7±0.9)℃。经过不同温度孵化10d后蝌蚪的最适温度、逃避温度和致死温度都存在显著差异。     

Behavioral thermoregulation, temperature tolerance and oxygen consumption in the Mexican bullseye puffer fish, Sphoeroides annulatus Jenyns (1842), acclimated to different temperatures

An inverse and unusual relationship was found between preferred temperature and acclimation temperature in the bullseye puffer, Sphoeroides annulatus. The final preferendum temperature (PT) was 26.8 °C. The critical thermal maxima (CTMax) were 37.7, 38.8, 40.0, 40.8 and 41.3 °C where the temperatures of acclimation were 19, 22, 25, 28 and 31 °C±1 °C, respectively, and the endpoint of CTMax was loss of the righting response. The acclimation response ratio presented an interval of 0.22-0.38; these values are in agreement with results for other subtropical and tropical fishes. The temperature significantly affected the oxygen consumption of bullseye puffer juveniles. The oxygen consumption rate (OCR) increased significantly with an increment in the temperature from 19 to 31 °C. The range of the temperature coefficient Q₁₀ in bullseye puffer individuals was lowest between 25 and 28 °C, at 1.37. The optimal temperature for growth was 26 °C. The results of this study will be useful for optimizing the culture of bullseye puffer juveniles in controlled conditions.     

Preferred ambient temperature for old and young men in summer and winter

To investigate the effects of age on thermal sensitivity, preferred ambient temperature (T _pref) was compared between old (71–76 years) and young (21–30 years) groups, each consisting of six male subjects in summer and winter. The air temperature (T _a) was set at either 20° C or 40° C at commencement. The subject was directed to adjust theT _a for 45 min by manipulating a remote control switch to the level at which he felt most comfortable. In the older group, theT _pref was significantly lower in trials starting at 20° C than that starting at 40° C in summer. The fluctuation ofT _pref (temperature difference between maximum and minimumT _a during the last 10 min) was significantly wider in the older group in both summer and winter. Repetition of the same experiment on each subject showed a poorer reproducibility ofT _pref in the older group than in the younger group in summer. Tympanic and esophageal temperatures of the older group kept falling throughout the trial starting at 20° C in summer. These results suggest that thermal sensitivity is decreased with advancing age and that thermal perception in the elderly, especially to cold, is less sensitive in summer.     

Thermal ecology of juvenile steelhead in a warm-water environment

How salmonids adjust to the cost of chronic exposure to warm water in nature, particularly in habitats where areas of cold water are unavailable, is largely unknown. In the hot dry climate of southern California, oversummering juvenile steelhead, Oncorhynchus mykiss, can experience a continual warm-water environment. Studies were performed in three streams (34°N) during the summers of 2002–2004 to assess how steelhead (10–28 cm total length) exploit the thermal environment and to develop an understanding of how existing preference and heat tolerance information reported for the species relate to the actual temperatures the local population experiences. Analyses of achievable body temperatures, an index of observed body temperatures, and behavioral time budgets, indicate steelhead did not behaviorally thermoregulate. Findings from associated field surveys suggest areas of cold water were not available. Steelhead held focal points at temperatures (17.4–24.8°C) that were at times higher than the temperature preferences and heat tolerances reported for the species. Oversummering juvenile steelhead accept an elevated body temperature and remain active and forage throughout the day, apparently as a means for coping with warm water at the southern extent of their range. The relatively high body temperatures that steelhead accept appear to represent a compromise in exchange for maintaining an expanded geographic (latitudinal) range.     

Thermal preference and tolerance of Megastrea (Lithopoma) undosa (Wood, 1828; Gastropoda: Turbinidae)

The thermoregulatory behavior of the wavy turban snail Megastrea (Lithopoma) undosa was determined in a horizontal thermal gradient and was 16.31 in day cycle and 14.4 °C in night cycle. Displacement velocity of adults was 29.3±4.2 cm h⁻¹ during the light phase and 26.1±3.2 cm h⁻¹ during the dark phase. The critical thermal maxima of the wavy turban snail were determined. As a measure of thermal tolerance, snails were subjected to increasing water temperatures at a rate of 1 °C every 30 min until they were detached from the substrate. The critical thermal maximum at 50% was 29.7 °C.     

Assessing population and environmental effects on thermal resistance in Drosophila melanogaster using ecologically relevant assays

To make laboratory studies of thermal resistance in ectotherms more ecologically relevant, temperature changes that reflect conditions experienced by individuals in nature should be used. Here we describe an assay that is useful for quantifying multiple measures of thermal resistance of individual adult flies. We use this approach to assess upper and lower thermal limits and functional thermal scope for Drosophila melanogaster and also show that the method can be used to (1) detect a previously described latitudinal cline for cold tolerance in D. melanogaster populations collected along the east coast of Australia, (2) demonstrate that acclimation at variable temperatures during development increases tolerance to both low and high thermal stresses and therefore increases thermal scope compared to acclimation at a constant temperature, (3) show that temperate populations adapted to variable thermal environments have wider thermal limits compared to those from the less variable tropics, at least when flies were reared under constant temperature conditions and (4) demonstrate that different measures of cold resistance are often not strongly correlated. Based on our findings, we suggest that the method could be routinely used in evaluating thermal responses potentially linked to ecological processes and evolutionary adaptation.     

Thermal preferenda and behavior of Atlantic eels (genus Anguilla) in relation to their spawning migration

Synopsis The final preferred temperatures (FPTs) of adult premigratory and migratory life-history phases of American eels, Anguilla rostrata, were determined by chronic tests in a horizontal thermal gradient. Mean FPTs were between 17 and 20°C and were not significantly different between life-history phases, acclimation temperatures, illumination regimes, photoperiods or sexual maturation states. Thermal behavior of eels was highly variable, both among individuals of the various test groups and among repeated tests of single individuals. Light inhibited behavioral thermoregulation by promoting shelter-seeking. The following inferences are drawn from the laboratory findings and observations of migrating A. rostrata and A. anguilla (European eels) in the North Atlantic: (1) decreasing temperatures may initiate downstream migration of silver eels, (2) eels may select temperatures close to their FPT in thermally stratified environments, but will tolerate higher and lower temperatures depending on illumination or other physical constraints, (3) the oceanic phase of the migration to the Sargasso Sea may take place at relatively shallow depths in the open ocean, probably within the upper 1000 meters. The strong eurythermality observed in eels may facilitate their occupation of and migration through thermally diverse and unpredictable habitats.     

恒温驯化对中国林蛙热耐受性的影响

外温动物主要利用外热源,选择活动时间和冷热斑块之间穿梭等行为途径进行体温调节,以维持相对较高且稳定的体温。环境温度通过影响体温而影响动物的生理功能和行为表现.过高或过低的体温对动物有害甚至能导致其死亡,在极端高、低体温之间,相对较高的体温有利于动物较好地表达其生理功能和行为表现。[第一段]     

Thermoregulatory activity in the Tecopa pupfish,Cyprindon nevadensis amargosae,an inhabitant of a thermal spring

Synopsis The final thermal preferendum of Tecopa pupfish Cyprinodon nevadensis amargosae collected from a thermal spring was determined in the laboratory in spatial and temporal thermal gradients. Temperatures chosen centred around 30°C — a value close to those reported for other warmwater species in the literature. Upper limits to final preferenda and thermal tolerance in all species of fish are proposed.     

Validation of a new telemetric core temperature monitor

The purpose of this study was to validate the accuracy and acceptability of the new VitalSense^® telemetric physiological monitoring system (Mini Mitter Co., Inc., Bend, OR). It consists of a receiver/monitor and a thermistor-based ingestible capsule for core body temperature measurement. For comparison, each subject was also monitored with a standard thermistor probe inserted 11 cm beyond the anal sphincter (Mini-Logger^® Series 2000). Both the measurement systems have specified accuracy of ±0.1 °C.

Ten volunteers, four females, six males, mean age 51.1±11.8 years, gave informed consent to wear the two systems for the duration of the passage of the temperature capsule through their digestive tracts. Minute-by-minute comparisons were made between the temperatures recorded by the two systems. Parameters reported include: average transit time of the capsule; temperature at each minute of the experiment; mean difference in temperature at each time point; correlation coefficient for the two temperature measurements; and number of missed data points for each system.

Mean capsule transit time was 48.6±35.5 h with a range of 12.4–136.2 h. The mean temperature for all subjects was 36.93 °C±0.15 °C and 36.96 °C±0.16 °C for the capsule and rectal probe respectively, with no significant difference between the means. The mean difference between readings (capsule–rectal probe) was 0.04 °C±0.03 °C. There was a significant correlation between the capsule and rectal probe temperatures, R²=0.80,p<0.05 and R²=0.90,p<0.05 for all data points and quiescent periods respectively. Of the average 2916±2132 data points per subject, there was a significant (p<0.05) difference in data points lost, 105±120 with VitalSense vs. 449±697 with the rectal probe. The percentage of missing data points was 3.1%±2.5% for the capsule (monitor out of the one-meter range of the capsule) and 11.4%±15.9% for the rectal probe (primarily due to probe slippage, but also due to removal for personal hygiene). The data support the finding that the VitalSense core body temperature monitoring system is at least as accurate as rectal probe monitors and the subjects found it to be much more acceptable.     

Interindividual differences in thermal comfort and the responses to skin cooling in young women

The present study aims to understand the effects of interindividual differences in thermal comfort on the relationship between the preferred temperature and the thermoregulatory responses to ambient cooling. Thirteen young women subjects chose the preferred ambient temperature (preferred T_a) in a climate chamber and were categorized into the H group (preferring ≥29 °C; n=6) and the M group (preferring <29 °C; n=7). The H group preferred warmer sensations than the M group (P<0.05) and the average of preferred T_a was 27.6 °C and 30.2 °C in the M group and H group, respectively. Then all subjects were exposed to temperature variations in the climate chamber. During T_a variations from 33 °C to 25 °C, the H group felt colder than the M group, although no difference was noted in the T_sk (mean skin temperature) and T_s-hand between the 2 groups. From the view of the relationship between the T_sk and thermal sensation, although the thermal sensitivity to the T_sk was almost similar in the H and M groups, the H group might have lower threshold to decreasing T_a than the M group.     

多疣壁虎的体温调节及运动能力热依赖性

本文测定了多疣壁虎(Gekko japonicus)的野外活动体温、喜好体温以及运动能力热依赖性,探讨夜行性蜥蜴的体温调节及其对动物功能表达的作用。在自然条件下,多疣壁虎的活动体温存在明显的月份间差异,但无性别和年龄间的差异。在实验室条件下,怀卵雌体(29.8℃)和幼体(29.9℃)的喜好体温显著高于非怀卵雌体(28.5℃)和雄体(28.2℃)。体温能显著影响多疣壁虎的运动能力,在15℃-34℃范围内,其平均跑速随体温上升而加快,超过34℃后则随体温升高而减慢。多疣壁虎的平均跑速及其热敏感性无显著的年龄组间差异。在夜间活动期,雄体、非怀卵雌体和幼体的体温调节有效度低,而怀卵雌体的体温调节有效度则较高。结果显示怀卵雌体的体温调节较非怀卵雌体和雄体更精确