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。     

热耐受性及温度对食物同化的影响

研究变色树蜥(Calotes versicolor)的选择体温、热耐受性、温度对食物同化的影响.结果显示:①幼体的选择体温、临界高温和临界低温的平均值分别为32.6、41.7℃和 7.7℃;成体的选择体温、临界高温和临界低温的平均值分别为33.1、42.0℃和8.2℃.②环境温度在26～34℃时,对变色树蜥食物通过时间和摄入能有显著的影响;对表观消化系数(ADC)和同化效率(AE)无显著的影响;在28～34℃时食物通过时间随温度升高而缩短;在26、28℃和30℃时,摄入能小于更高温度的对应值.     

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。     

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]。     

摄食对原尾蜥虎代谢率的影响

通过测定摄食后原尾蜥虎成体的耗氧量变化,研究摄食特殊热动力作用（SDA）.蜥虎分为摄食黄粉虫幼虫实验组和禁食对照组,两组动物平均体重无显著差异.测定耗氧量前,将所有动物在30℃恒温室内禁食3天.用容积为300 ml的封闭式呼吸室测定两组蜥虎在30℃条件下连续3天的耗氧量,测定间隔时间为4～12 h.禁食组动物实验期间的耗氧量无显著的时间变异,实验组动物耗氧量的时间变异显著,这些结果表明摄食影响原尾蜥虎的代谢率.实验组动物摄食4 h后耗氧量已显著大于禁食组,摄食40 h后两组动物的耗氧量无显著差异.原尾蜥虎达到SDA峰值的平均时间约为20.0 h,SDA峰值耗氧量是禁食对照组动物耗氧量的1.5倍.原尾蜥虎单次摄食实验中的SDA具有进食后耗氧量迅速增加、达到峰值后下降至摄食前水平的典型模式.     

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。     

泽陆蛙和饰纹姬蛙蝌蚪不同热驯化下选择体温和热耐受性

用泽陆蛙（Fejervarya limnocharis）蝌蚪和饰纹姬蛙（Microhyla ornata）蝌蚪做研究模型,检测热驯化（20 、25 和30 C）对选择体温（Tsel）、低温耐受性（CTMin）和高温耐受性（CTMax）的影响。结果显示,两种蝌蚪的Tsel既不受驯化温度的影响,也不存在种间差异;泽陆蛙蝌蚪的CTMin显著小于饰纹姬蛙蝌蚪,而CTMax和VTR则显著大于饰纹姬蛙蝌蚪;CTMin和CTMax随驯化温度的升高而升高,VTR则随驯化温度的升高而减小。研究结果表明,热驯化显著影响两种蝌蚪的CTMin、CTMax和VTR,而对两种蝌蚪的体温调定点无显著影响;这些热生物学特征对两种蝌蚪有效适应环境温度变化、利用资源、减少种间竞争具有重要的生态学意义。     

蜓和蓝尾石龙子幼体食物同化的热依赖性

用采自安徽滁州琅琊山的蜓(Sphenomorphus indicus,头体长42.8-54.4 mm,n=12)和蓝尾石龙子(Eumeces elegans,头体长43.9-57.3 mm,n=10)幼体,研究温度(24-32℃)对蜓和蓝尾石龙子幼体食物通过时间、摄食量、表观消化系数(ADC)、同化效率(AE)和生长的影响。结果显示,24-30℃范围内,蜓和蓝尾石龙子幼体的食物通过时间随温度的升高而缩短,超过30℃则基本不变。蜓幼体：30和32℃摄食量和生长小于24-28℃;24-30℃ ADC、AE随温度升高而下降,但32℃时又升高。蓝尾石龙子幼体：24-26℃摄食量随温度升高而增加,26℃后随温度升高显著下降;24-28℃ ADC、AE大于30和32℃,呈现出随温度升高而下降的趋势;26℃生长最快。结果表明,蜓和蓝尾石龙子幼体的摄食和同化能力均低于相应的成体。     

蝘蜓和蓝尾石龙子幼体食物同化的热依赖性

用采自安徽滁州琅琊山的蝘蜓(Sphenomorphus indicus,头体长42．8～54．4mm,n=12)和蓝尾石龙子(Eumeces elegans,头体长43,9～57．3mm,n=10)幼体,研究温度(24～32℃)对蝘蜓和蓝尾石龙子幼体食物通过时间、摄食量、表观消化系数(ADC)、同化效率(AE)和生长的影响。结果显示,24～30℃范围内,蝘蜓和蓝尾石龙子幼体的食物通过时间随温度的升高而缩短,超过30℃则基本不变。蝘蜓幼体：30和32℃摄食量和生长小于24～28℃;24～30℃．ADC、AE随温度升高而下降,但32℃时又升高。蓝尾石龙子幼体：24～26℃摄食量随温度升高而增加,26℃后随温度升高显著下降;24～28℃ADC、AE大于30和32℃,呈现出随温度升高而下降的趋势;26℃生长最快。结果表明,蝘蜓和蓝尾石龙子幼体的摄食和同化能力均低于相应的成体。     

蜓和蓝尾石龙子幼体食物同化的热依赖性

用采自安徽滁州琅琊山的(虫匽)蜓(Sphenomorphus indicus,头体长42.8～54.4mm,n=12)和蓝尾石龙子(Eumeces elegans,头体长43.9～57.3mm,n=10)幼体,研究温度(24～32℃)对(虫匽)蜓和蓝尾石龙子幼体食物通过时间、摄食量、表观消化系数(ADC)、同化效率(AE)和生长的影响.结果显示,24～30℃范围内,(虫匽)蜓和蓝尾石龙子幼体的食物通过时间随温度的升高而缩短,超过30℃则基本不变.(虫匽)蜓幼体30和32℃摄食量和生长小于24～28℃;24～30℃ADC、AE随温度升高而下降,但32℃时又升高.蓝尾石龙子幼体24～26℃摄食量随温度升高而增加,26℃后随温度升高显著下降;24～28℃ADC、AE大于30和32℃,呈现出随温度升高而下降的趋势;26℃生长最快.结果表明,(虫匽)蜓和蓝尾石龙子幼体的摄食和同化能力均低于相应的成体.     

Disentangling thermal preference and the thermal dependence of movement in ectotherms

Many ectotherms thermoregulate by choosing environmental temperatures that maximize diverse performance traits, including fitness. For this reason, physiological ecologists have measured preferred temperatures of diverse ectotherms for nearly a century. Thermal preference is usually measured by observing organism distributions on laboratory thermal gradients. This approach is appropriate for large ectotherms which have sufficient thermal inertia to decouple body temperatures from gradient temperatures. However, body temperatures and therefore speeds of movement of small ectotherms will closely track gradient temperature, making it difficult to distinguish between thermal preference and thermal dependence of movement. Here we develop and demonstrate the use of a patch model to derive the expected thermal gradient distribution given only the thermal dependence of movement. Comparison of this null distribution with the observed gradient distribution reveals thermal preference of small ectotherms.     

Testing the thermal limits of Eccritotarsus catarinensis: a case of thermal plasticity

Water hyacinth is considered the most damaging aquatic weed in South Africa. The success of biocontrol initiatives against the weed varies nation-wide, but control remains generally unattainable in higher altitude, temperate regions. Eccritotarsus catarinensis (Hemiptera: Miridae) is a biocontrol agent of water hyacinth that was first released in South Africa in 1996. By 2011, it was established at over 30 sites across the country. These include the Kubusi River, a site with a temperate climate where agent establishment and persistence was unexpected. This study compared the critical thermal limits of the Kubusi River insect population with a laboratory-reared culture to determine whether any physiological plasticity was evident that could account for its unexpected establishment. There were no significant differences in critical thermal maxima (CT_max) or minima (CT_min) between sexes, while the effect of rate of temperature change on the thermal parameters in the experiments had a significant impact in some trials. Both CT_max and CT_min differed significantly between the two populations, with the field individuals tolerating significantly lower temperatures (CT_min: ?0.3°C?±?0.063 [SE], CT_max: 42.8°C?±?0.155 [SE]) than those maintained in the laboratory (CT_min: 1.1°C?±?0.054 [SE], CT_max: 44.9°C?±?0.196 [SE]). Acclimation of each population to the environmental conditions typical of the other for a five-day period illustrated that short-term acclimation accounted for some, but not all of the variation between their lower thermal limits. This study provides evidence for the first cold-adapted strain of E. catarinensis in the field, with potential value for introduction into other colder regions where water hyacinth control is currently unattainable.     

Sex differences in thermal detection and thermal pain threshold and the thermal grill illusion: a psychophysical study in young volunteers

Background

Sex-related differences in human thermal and pain sensitivity are the subject of controversial discussion. The goal of this study in a large number of subjects was to investigate sex differences in thermal and thermal pain perception and the thermal grill illusion (TGI) as a phenomenon reflecting crosstalk between the thermoreceptive and nociceptive systems. The thermal grill illusion is a sensation of strong, but not necessarily painful, heat often preceded by transient cold upon skin contact with spatially interlaced innocuous warm and cool stimuli.

Methods

The TGI was studied in a group of 78 female and 58 male undergraduate students and was evoked by placing the palm of the right hand on the thermal grill (20/40 °C interleaved stimulus). Sex-related thermal perception was investigated by a retrospective analysis of thermal detection and thermal pain threshold data that had been measured in student laboratory courses over 5 years (776 female and 476 male undergraduate students) using the method of quantitative sensory testing (QST). To analyse correlations between thermal pain sensitivity and the TGI, thermal pain threshold and the TGI were determined in a group of 20 female and 20 male undergraduate students.

Results

The TGI was more pronounced in females than males. Females were more sensitive with respect to thermal detection and thermal pain thresholds. Independent of sex, thermal detection thresholds were dependent on the baseline temperature with a specific progression of an optimum curve for cold detection threshold versus baseline temperature. The distribution of cold pain thresholds was multi-modal and sex-dependent. The more pronounced TGI in females correlated with higher cold sensitivity and cold pain sensitivity in females than in males.

Conclusions

Our finding that thermal detection threshold not only differs between the sexes but is also dependent on the baseline temperature reveals a complex processing of “cold” and “warm” inputs in thermal perception. The results of the TGI experiment support the assumption that sex differences in cold-related thermoreception are responsible for sex differences in the TGI.

     

Tissue temperature profile in the human forearm during thermal stress at thermal stability.

The purpose of the present study was to investigate the effect of a range of water temperatures (Tw from 15 to 36 degrees C) on the tissue temperature profile of the resting human forearm at thermal stability. Tissue temperature (Tti) was continuously monitored by a calibrated multicouple probe during 3 h of immersion of the forearm. The probe was implanted approximately 9 cm distal from the olecranon process along the ulnar ridge. Tti was measured every 5 mm, from the longitudinal axis of the forearm (determined from computed tomography scanning) to the skin surface. Along with Tti, skin temperature (Tsk), rectal temperature (Tre), and blood flow were measured during the immersions. For all temperature conditions, the temperature profile inside the limb was linear as a function of the radial distance from the forearm axis (P less than 0.001). Temperature gradient measured in the forearm ranged from 0.2 +/- 0.1 degrees C C cm (Tw = 36 degrees C) to 2.3 +/- 0.5 degrees C cm (Tw = 15 degrees C). The maximal Tti was measured in all cases at the longitudinal axis of the forearm and was in all experimental conditions lower than Tre. On immersion at Tw less than 36 degrees C, the whole forearm can be considered to be part of the shell of the body. With these experimental data, mathematical equations were developed to predict, with an accuracy of at least 0.6 degrees C, the Tti at any depth inside the forearm at steady state during thermal stress.(ABSTRACT TRUNCATED AT 250 WORDS)     

Perception of thermal pain and the thermal grill illusion is associated with polymorphisms in the serotonin transporter gene

Aim

The main aim of this study was to assess if the perception of thermal pain thresholds is associated with genetically inferred levels of expression of the 5-HT transporter (5-HTT). Additionally, the perception of the so-called thermal grill illusion (TGI) was assessed. Forty-four healthy individuals (27 females, 17 males) were selected a-priori based on their 5-HTTLPR/rs25531 (‘tri-allelic 5-HTTLPR’) genotype, with inferred high or low 5-HTT expression. Thresholds for heat- and cold-pain were determined along with the sensory and affective dimensions of the TGI.

Results

Thresholds to heat- and cold-pain correlated strongly (rho  = −0.58, p<0.001). Individuals in the low 5-HTT-expressing group were significantly less sensitive to heat-pain (p = 0.02) and cold-pain (p = 0.03), compared to the high-expressing group. A significant gender-by-genotype interaction also emerged for cold-pain perception (p = 0.02); low 5-HTT-expressing females were less sensitive. The TGI was rated as significantly more unpleasant (affective-motivational dimension) than painful (sensory-discriminatory dimension), (p<0.001). Females in the low 5-HTT expressing group rated the TGI as significantly less unpleasant than high 5-HTT expressing females (p<0.05), with no such differences among men.

Conclusion/Significance

We demonstrate an association between inferred low 5-HTT expression and elevated thresholds to thermal pain in healthy non-depressed individuals. Despite the fact that reduced 5-HTT expression is a risk factor for chronic pain we found it to be related to hypoalgesia for threshold thermal pain. Low 5-HTT expression is, however, also a risk factor for depression where thermal insensitivity is often seen. Our results may thus contribute to a better understanding of the molecular underpinnings of such paradoxical hypoalgesia. The results point to a differential regulation of thermoafferent-information along the neuraxis on the basis of 5-HTT expression and gender. The TGI, suggested to rely on the central integration of thermoafferent-information, may prove a valuable tool in probing the affective-motivational dimension of these putative mechanisms.     

Thermophilic blue-green algae and the thermal environment

[This corrects the article on p. 485 in vol. 33.].