雄性山地麻晰选择体温、热耐受性及温度对食物同化和运动表现的影响

研究了捕自安徽宿州的成年雄性山地麻蜥（Eremias brenchleyi）选择体温、热耐受性、温度对食物同化和运动表现的影响。结果显示：①选择体温、临界高温和临界低温的平均值分别为33.7、43.6和3.3℃。②环境温度在26－38℃时,对山地麻蜥食物通过时间、摄食量、表观消化系数（ADC）、同化效率（AE）和运动表现有显著的影响;在26－30℃时食物通过时间随温度升高而缩短,通过30℃则随温度升高而延长;在26和28℃时,摄食量、ADC和AE均小于更高温度的对应值。③体温在19－34℃,蜥蜴的疾跑速随体温上升而加快,31和34℃时最快,超过34℃后随体温升高而减慢;31和34℃时的持续运动距离最长,超过36℃后随体温升高而显著缩短,但体温19－36℃蜥蜴的持续运动距离无显著差异;19－34℃蜥蜴的路道停顿次数较少,无显著差异,超过34℃后显著增加。     

雄性山地麻蜥选择体温、热耐受性及温度对食物同化和运动表现的影响

研究了捕自安徽宿州的成年雄性山地麻蜥 (Eremiasbrenchleyi)选择体温、热耐受性、温度对食物同化和运动表现的影响。结果显示 :①选择体温、临界高温和临界低温的平均值分别为 33 7、 43 6和 3 3℃。②环境温度在 2 6～ 38℃时 ,对山地麻蜥食物通过时间、摄食量、表观消化系数 (ADC)、同化效率 (AE)和运动表现有显著的影响 ;在 2 6～ 30℃时食物通过时间随温度升高而缩短 ,超过 30℃则随温度升高而延长 ;在 2 6和 2 8℃时 ,摄食量、ADC和AE均小于更高温度的对应值。③体温在 19～ 34℃ ,蜥蜴的疾跑速随体温上升而加快 ,31和 34℃时最快 ,超过 34℃后随体温升高而减慢 ;31和 34℃时的持续运动距离最长 ,超过 36℃后随体温升高而显著缩短 ,但体温 19～ 36℃蜥蜴的持续运动距离无显著差异 ;19～ 34℃蜥蜴的跑道停顿次数较少 ,无显著差异 ,超过 34℃后显著增加。     

华北丽斑麻蜥食物同化和疾跑速的热依赖性

作者研究山西阳泉丽斑麻蜥(Eremias argus)成体的选择体温、热耐受性及食物同化和疾跑速的热依赖性。选择体温、临界低温和临界高温无显著的两性差异,分别为36·0℃、1·0℃和44·9℃。在实验温度范围内,体温显著影响食物通过时间、日摄食量、日粪尿排量、表观消化系数和同化效率。食物通过时间在26 -34℃范围内随体温升高而缩短,在更高的体温下则延长。蜥蜴在30、32、34和36℃体温下明显摄入较多的食物、排出明显较多的粪尿。34℃和36℃下的表观消化系数和同化效率大于其它更低或更高温度下的对应数值,但这两个变量未因体温变化而呈现清晰的规律性变化。疾跑速在18 -36℃范围内随体温升高而加快,在38℃体温下则减缓。36℃或附近体温最适合疾跑速。疾跑速最适体温接近蜥蜴的选择体温,表明蜥蜴疾跑速的最适温度可能与其选择体温密切相关[动物学报52 (2) : 256 -262 , 2006]。     

原尾蜥虎的选择体温、热耐受性和食物同化的热依赖性

(Tsel)、热耐受性和体温对食物同化的影响。Tsel无显著的日时间变化,两性个体的Tsel、临界低温(CTMin)和临界高温(CTMax)无显著的差异。Tsel、CTMin和CTMax的平均值分别为30.9℃、3.2℃和43.3℃。体温对动物食物通过时间有显著的影响。在25℃-33℃范围内,食物通过时间随体温升高而缩短;体温超过33℃后,食物通过时间随体温升高而延长。温度对原尾蜥虎的摄食量、表观消化系数(ADC)和同化效率(AE)有显著的影响。在25℃-37℃范围内,动物在低体温下(25℃和27℃)的摄食量、ADC和AE小于更高体温下动物的对应数值。种间比较结果显示,原尾蜥虎是生活于南方的蜥蜴中具有较强耐受极端体温的种类。     

青海沙蜥的热耐受性、选择体温及摄食和运动表现的热依赖性

研究了青海沙蜥(Phrynocephalus vlangalii)成体的选择体温、热耐受性及食物同化和运动表现的热依赖性。结果显示:选择体温、临界低温和临界高温无显著的两性差异,其平均值分别为33.3、0.9℃和46.9℃。在27-35℃实验温度范围内,体温显著影响日摄食量,表观消化系数(ADC)和同化效率(AE)无显著影响。停顿次数随着体温的升高而降低,至39℃时停顿次数最少,但与37℃和41℃处理下的停顿次数无显著差异。疾跑速在17-39℃范围内随体温升高而加快,在39℃体温下最快。体温大于39℃后速度减慢。在17-27℃体温范围内,随体温的升高持续运动距离无显著差异。持续运动距离在29-41℃体温下大于较低体温(17-27℃)下的测定值。     

中国石龙子热生物学的研究

通过研究中国石龙子选择体温，临界温度与实验温度对该种的体温，疾跑速，摄食量，食物通过时间，表现消化系数，同化效率和生长的影响发现，中国石龙子选择体温３１．２℃，临界高，低温分别为４２．３和６．３℃，恒温室内中国石龙子的体温与实验温度接近，温度对中国石龙子的疾跑速有显著影响，３４℃中动物疾跑速最高，过高或过低实验温度中的动物疾跑减慢，温度对中国石龙子食物通过时间，单位体重摄食量，粪尿能值，表观消化系     

中华花龟幼体热耐受性、体温昼夜变化和运动表现的热依赖性

为研究中华花龟(Ocadia sinensis)幼体的热耐受性和运动表现热依赖性，设计了具有和缺乏温度梯度两种热环境，研究幼龟体温的昼夜变化。高、低温耐受性分别用临界高温和临界低温表示，体温为泄殖腔温度，水温和气温分别是幼龟所处位置的水温和1cm高气温。临界高温和临界低温分别为41．9℃和1．8℃。在有温度梯度的热环境中，体温、水温和气温平均值有显著的昼夜差异，水温和体温的日平均值无显著差异，两者均大于气温的日平均值。在缺乏温度梯度的热环境中，体温、气温和水温平均值亦有显著的昼夜差异，但气温、水温和体温的日平均温度无显著差异。温度梯度是幼龟进行体温调节不可或缺的条件，选择体温有显著的昼夜变化，最大值和最小值分别为29．2℃和25．4℃。在02：00—06：00时间段内，幼龟选择体温明显较低，其它测定时刻的选择体温无显著差异。幼龟各测定时刻的平均体温与平均气温和水温均呈正相关。处于温度梯度中幼龟特定气温的体温比处于缺乏温度梯度中的幼龟高3．7℃，这种差异是前者利用温度梯度进行体温调节的结果；处于不同热环境中幼龟特定水温的体温无显著差异。体温显著影响幼龟的运动表现。18—39℃体温范围内，疾跑速随体温增加而增加，36℃和39℃体温的幼龟疾跑速最大；体温达到41℃时，疾跑速显著下降。体温较高的幼龟的最大持续运动距离大于体温较低的幼龟。偏相关分析显示，疾跑速与最大持续运动距离和停顿次数呈显著的正相关，停顿次数与最大持续运动距离呈负相关。     

环境温度对(虫)蜓能量需求和食物同化影响的研究

研究了环境温度对成体Yan蜓能量需求和食物同化的影响。在24℃—33℃范围内,雌、雄Yan蜓摄入能、表观消化系数和同化效率的两性差异不显著。温度显著影响Yan蜓的能量摄入和同化效率,27℃时的能量摄入显著高于30℃和33℃,27℃时的同化效率显著高于24℃和33℃。各实验温级表观消化系数的差异不显著。结果表明：环境温度对Yan蜓能量需求和食物同化的影响显著。     

斑马鱼热耐受性对温度驯化的响应及其性别差异

为了探究斑马鱼(Danio rerio)热耐受性对温度驯化的响应及其性别差异,将性成熟斑马鱼分别于适温(28℃)、低温(20℃)和高温(34℃)下驯化14 d,之后测定不同温度驯化下雌鱼和雄鱼的临界高温(critical thermal maxima,CTmax)、致死高温(lethal thermal maxima,LTmax)、临界低温(critical thermal minima,CTmin)、致死低温(lethal thermal minima,LTmin)等热耐受性参数.结果表明:驯化温度对雄鱼和雌鱼的所有热忍耐参数(CTmax、LTmax、CTmin和LTmin)均影响显著(P<0.05),并且驯化温度和性别对热耐受性参数的影响具有交互作用(P<0.05).适温(28℃)驯化下,雌鱼与雄鱼各个热忍耐参数相比无显著差异(P> 0.05);低温(20℃)驯化下雌鱼的耐高温能力强于雄鱼,而高温(34℃)驯化下雌鱼的耐低温能力弱于雄鱼.结果提示:繁殖适温下雌雄斑马鱼的热耐受性趋于一致,而非繁殖适温下二者的热耐受性出现分化.     

Activity, blood temperature and brain temperature of free-ranging springbok

We used miniature data loggers to record temperature and activity in free-ranging springbok (Antidorcas marsupialis) naturally exposed to severe nocturnal cold and moderate diurnal heat. The animals were active throughout the day and night, with short rests; the intensity of activity increased during daylight. Arterial blood temperature, averaged over many days, exhibited a circadian rhythm with amplitude <1 °C, but with a wide range which resulted from sporadic rapid deviations of body temperature. Peak blood temperature occurred after sunset. Environmental thermal loads had no detectable effect on blood temperature, even though globe temperature varied by >10 °C from day to day and >20 °C within a day. Brain temperature increased approximately linearly with blood temperature but with a slope <1, so that selective brain cooling tended to be activated at high body temperature, but without a precise threshold for the onset of brain cooling. Low activity attenuated selective brain cooling and high activity abolished it, even at high brain temperature. Our results support the concept that selective brain cooling serves to modulate thermoregulation rather than to protect the brain against heat injury. Accepted: 7 January 1997     

Chill-coma temperature in Drosophila: effects of developmental temperature, latitude, and phylogeny

We modify and apply a nonlethal technique for rapidly quantifying the cold tolerance of large numbers of Drosophila and other small insects. Flies are transferred to individual vials, cooled in groups in progressive 0.5 degrees C steps, and checked for loss of righting response (chill-coma temperature [T(cc)]). Flies recover quickly when transferred to ambient temperature, and thus this technique potentially can be used in selection experiments. We applied this technique in several experiments. First, we examined the sensitivity of T(cc) to developmental temperature. Drosophila melanogaster (Congo, France), Drosophila subobscura (Spain, Denmark), and Drosophila ananassae (India) were reared from egg to adult at 15 degrees, 18 degrees, 25 degrees, or 29 degrees C, transferred to 15 degrees C for several days, and then progressively chilled: T(cc) was positively related to developmental temperature, inversely related to latitude of the population, but independent of sex. The sensitivity of T(cc) to developmental temperature (acclimation flexibility) was marked: T(cc) shifted on average 1 degrees for each 4 degrees C shift in developmental temperature. Among 15 species of the obscura group of Drosophila, T(cc) varied from -0.1 degrees to 4.5 degrees C; T(cc) was inversely related to latitude in both nonphylogenetic and phylogenetically based ANCOVA (standardized independent contrasts) and was unrelated to body size.     

Light, temperature, and anthocyanin production

Temperature affects the total amount, the time course, and the red/far-red effectiveness ratio of light-dependent anthocyanin production in Brassica oleracea L. seedlings. Some of the effects of temperature on anthocyanin production in cabbage are in agreement with the predictions of a model proposed by JK Wall and CB Johnson (1983 Planta 159: 387-397) for the effects of temperature on the state of phytochrome and on the expression of phytochrome-mediated high irradiance responses, but others are not. The lack of a complete agreement between experimental results and model predictions might be due to factors related to the experimental system used or to limitations of the model or both.     

Water, temperature and life

Cold is the fiercest and most widespread enemy of life on earth. Natural cold adaptation and survival are discussed in terms of physicochemical and biochemical water management mechanisms, relying on thermodynamic or kinetic stabilization. Distinctions are drawn between general effects of low temperature (chill) and specific effects of freezing. Freeze tolerance is a misnomer because tolerance does not extend to the cell fluids. Freezing is confined to the extracellular spaces where it acts as a means of protecting the cytoplasm against freezing injury. Freeze resistance depends on the phenomenon of undercooling, a survival mechanism that relies on the long-term maintenance of a thermodynamically highly unstable state. Correct water management involves many factors, among them the control of membrane composition and transmembrane osmotic equilibrium, the biosynthesis of compounds able to afford protection against injury through freeze desiccation and the availability (or inactivation) of biogenic ice nucleation catalysts.     

Effects of temperature and wind on facial temperature, heart rate, and sensation.

Skin temperature measurements of the face have shown that the cheek cools faster than the nose and the nose faster than the forehead. The cooling effect of wind is maximum at wind speeds between 4.5 and 6.7 m/s. Cold winds produce significant bradycardia, which is, however, much more pronounced during the expiratory phase of respiration. A significant correlation was noted between cooling of face and the reflex bradycardia observed. Similarly, a very significant correlation was noted between drop in skin temperature and subjective evaluation of cold discomfort. Consequently, the drop in skin temperature, reflex bradycardia, and subjective evaluation are parameters which are directly affected by cold wind and can be used as adequate indicators of the degree of discomfort. When comparing the present results with the windchill index, it was found that in the zone described as "dangerously cold" the index fits well with the physiological measurements. In the zone described as "bitterly cold," the index by comparison with actual skin temperature measurements and subjective evaluation underestimates the cooling effects of combined temperature and wind by approximately 10 degrees C.     

Increasing temperature, not mean temperature, is a cue for avian timing of reproduction

Timing of reproduction in temperate-zone birds is strongly correlated with spring temperature, with an earlier onset of breeding in warmer years. Females adjust their timing of egg laying between years to be synchronized with local food sources and thereby optimize reproductive output. However, climate change currently disrupts the link between predictive environmental cues and spring phenology. To investigate direct effects of temperature on the decision to lay and its genetic basis, we used pairs of great tits (Parus major) with known ancestry and exposed them to simulated spring scenarios in climate-controlled aviaries. In each of three years, we exposed birds to different patterns of changing temperature. We varied the timing of a temperature change, the daily temperature amplitude, and the onset and speed of a seasonal temperature rise. We show that females fine-tune their laying in response to a seasonal increase in temperature, whereas mean temperature and daily temperature variation alone do not affect laying dates. Luteinizing hormone concentrations and gonadal growth in early spring were not influenced by temperature or temperature rise, possibly posing a constraint to an advancement of breeding. Similarities between sisters in their laying dates indicate genetic variation in cue sensitivity. These results refine our understanding of how changes in spring climate might affect the mismatch in avian timing and thereby population viability.     

Relationships between the circadian rhythms of finger temperature, core temperature, sleep latency, and subjective sleepiness

Skin temperature circadian rhythms have been explored relatively recently. It has been suggested that distal and proximal skin temperature changes play a role in the regulation of the core temperature circadian rhythm and sleepiness. The authors investigated the circadian finger and core temperature rhythms in conjunction with the circadian rhythms of subjective and objective sleepiness. Fourteen healthy, young, good sleepers participated in a modified constant-routine procedure in which palmar finger temperature, rectal temperature, subjective sleepiness, and objective sleep latency were measured half-hourly across a 48-h period of enforced wakeful bed rest. Individual curves were adjusted to the group mean temperature minimum time of 0500 h and averaged to create the 4 mean curves. The 5 possible cross-correlation curves between these 4 measures were calculated for half-hourly phase lags from 12 h before to 12 h after the group mean core temperature minimum time. Maximum cross-correlations for each curve suggested that finger temperature preceded core temperature by 3 h (r = -0.22), and subjective sleepiness followed core temperature by 0.5 h (r = -0.33) and objective sleepiness by 2 h (r = 0.29). Although these data are correlational, they are consistent with the notion that finger temperature changes drive core temperature changes, which determine changes of subjective and objective sleepiness.     

Naloxone, naltrexone and body temperature

The temperature effects of naloxone and naltrexone (1-30 mg/kg) were examined in well habituated male rats. These drugs had a similar time course and potency, producing a dose-dependent hypothermia followed several hours later by a hyperthermia. A subsequent study found that not only did 30 mg/kg of naloxone or naltrexone produce an equivalent hypothermia but this hypothermia was just as pronounced during the dark as in the light part of the cycle.