Effects of vitamin E on diurnal variation in rectal temperature of Black Harco pullets during the hot-dry season

Experiments were performed with the aims of determining rectal temperature (RT) fluctuations in pullets, and the effect of vitamin E administration on the fluctuations during the hot-dry season. The RT values in experimental pullets administered vitamin E orally at a daily dose of 30 mg/kg, were significantly (P<0.05) lower than that of control pullets administered only water (41.21±0.02 and 41.43±0.04 °C, respectively). The dry-bulb temperature was significantly (P<0.001) and positively correlated with RT in both experimental (r=0.800) and control (r=0.936) pullets. Vitamin E administration ameliorated the heat stress of the hot-dry season, and may enhance productivity of pullets during the season.     

Heat coma and its relationship to ocean dynamics in the oceanic sea skaters of Halobates (Heteroptera: Gerridae) inhabiting Indian and Pacific Oceans

This study was performed to clarify how weather and current dynamics affect the resistance to temperature change in the oceanic sea skaters, Halobates. Heat coma temperature (HCT) was measured for the adults and 5th instar larvae of four Halobates species collected from a fixed sampling location (12°00′N, 135°00′E ) in western tropical Pacific Ocean and from 13 locations in the eastern area of the India Ocean ranging from 08°00′N-06°00′S and 86°00-76°00′E. Both the gap temperature for heat coma (GTHC, mean±SD: 7.83±1.86 °C, n=32) and the heat coma temperature (HCP, 35.03±1.80 °C, n=32) of individuals collected from the Pacific Ocean, during the first half (10 days) of the sampling period at the fixed sampling point, were significantly higher than those during the second half (GTHC: 5.10±2.05 °C, n=63; HCP: 34.03±2.02 °C, n=63). The reduction in heat tolerance shown in the second half of the 20 day period may have been caused by a decrease in air temperature due to rainfall that occurred around the sampling point accompanied with the arrival of Typhoon No. 6.In the study of individuals collected from the Indian Ocean, significantly higher average GTHCs of >8 °C were recorded for the adult H. micans collected at 02°00′S and 06°00′S (89°00′E) than those at 0°00-8°00′N in the eastern Indian Ocean. Dynamic mixture of water from northern and southern currents occurs at 02°00-6°00′S of the Indian Ocean and might relate to such high heat tolerance.Temperature dynamics in the ocean habitat might directly affect the temperature resistance of the oceanic sea skaters.     

Diurnal, seasonal and sex variations in rectal temperature of African giant rats (Cricetomys gambianus, Waterhouse)

(1)

Rectal temperature (T_r) was measured in captive African giant rats (Cricetomys gambianus, Waterhouse), live-trapped in the Savannah during the harmattan, hot-dry and rainy seasons with the aim of determining diurnal, seasonal and sex patterns.

(2)

Mean (±SEM) T_r in the morning (37.16±0.04 °C) was lower (P<0.001) than the afternoon (37.49±0.03 °C) and evening (37.66±0.03 °C). There was no significant difference (P>0.05) between afternoon and evening T_r during the harmattan and rainy seasons, but the difference was significant (P<0.001) during the hot-dry season. Overall T_r was higher (P<0.001) during the hot-dry (38.03±0.03 °C) than harmattan (37.17±0.03 °C) and rainy (37.21±0.03 °C) seasons. T_r of bucks was lower than that of does (P<0.0001) during the harmattan and rainy seasons, but sex difference during the hot-dry season was not significant (P>0.05).

(3)

Base-line T_r values for the African giant rats are shown for the first time. Season, time of day and sex influence fluctuations in T_rs of African giant rats, and should be considered during diagnostic and clinical evaluations.

     

Body temperature responses of Savanna Brown goat to the harmattan and hot-dry season

Rectal and vaginal temperature responses of the Savanna Brown goat indigenous to the Nigerian guinea savanna were determined during the harmattan and the hot-dry season. Measurements were made at 06:00h and at 14:00h after 8h exposure to field conditions. At the 06:00h measurements during the harmattan, all animals were observed to shiver. A significant (P<0.01) positive correlation was found between rectal (T_re) and vaginal temperatures. During the harmattan, mean T_re was 38.2C at 06:00h and 39.7C at 14:00h; the mean difference, T_re was 1.5C. During the hot-dry season, T_re at 06:00h was 38.1C, and at 14:00h, 38.7; T_re was 0.6C. It is concluded that the harmattan is thermally more stressful than the hot-dry season and that passive thermolability may not be an important mechanism in the Savanna Brown goat in adaptation to thermal stress.     

Thermal preferences of hatchling saltwater crocodiles (Crocodylus porosus) in response to time of day,social aggregation and feeding

Three month old hatchling Crocodylus porosus with data loggers in their stomachs were placed in thermal gradients, in isolation (N=16) and in groups of 4 (N=8 groups; 32 individuals). Mean T_b and variation in T_b (SD) was not different whether individual crocodiles in isolation were fasted or fed, or if individuals were housed in isolation (I) or in groups (G). However, individuals in isolation (N=16) maintained slightly lower T_bs than those in groups (N=32) during the early morning (06:00–11:00 h). The overall mean T_b recorded for fasted individuals in the isolated and group treatments (N=48) was 30.9±2.3 °C SD, with 50% of T_bs (T_set) between 29.4 °C and 32.6 °C, and a voluntary maximum and minimum of 37.6 °C and 23.2 °C respectively. During the day (11:00–17:00 h), individuals in isolation and in groups selected the warmer parts of the gradient on land, where they moved little. Outside of this quiescent period (QP), activity levels were much higher and they used the water more. There was a strong diurnal cycle for fasted individuals in isolation and in groups, with T_b during the QP (31.9±2.09 °C; N=48) significantly higher than during the non-quiescent period (NQP: 30.6±2.31 °C). Thermal variation (SD) in T_b was relatively stable throughout the day, with the highest variation at around dusk and early evening (18:00–20:00 h), which coincided with a period of highest activity. The diurnal activity cycle appears innate, and may reflect the need to engage in feeding activity at the water's edge in the early evening, despite ambient temperatures being cooler, with reduced activity and basking during the day. If so, preferred T_b may be more accurately defined as the mean T_b during the QP rather than the NQP. Implications for the thermal environment best suited for captive C. porosus hatchlings are discussed.     

Remote sensing of physiological data: Impact of long term captivity on body temperature variation of the feral cat (Felis catus) in Australia,recorded via Thermochron iButtons

This study reports body temperature regulation (T_b) and circadian rhythms of undisturbed feral cats in their natural environment in Australia over a continuous period of three months. It furthermore compares these data with T_b data collected of feral cats, after a period of one year in captivity. In free-ranging, undisturbed feral cats, a distinct robust, regular circadian rhythm (strength of rhythm) (21–59.8%) with higher body temperature in the dark (active) phase (mean±STD: 39.2±0.27 °C) and significantly lower body temperature during the light (rest) phase (mean±STD: 38.1±0.47 °C, P<0.001) was found. The acrophase (time of the daily peak) of the three free-ranging cats investigated varied from 22:34 h (LG 2), 22:57 h (LG 1) to 23:17 h (LG 3). In the course of captivity, the cats’ circadian rhythms shifted from nocturnality to a diurnal tendency, with an acrophase ranging from 12:00 h (MtK 2), 12:23 h (MtK 1) to 16:25 h (MtK 3). This change in rhythmicity was accompanied by a significant decrease in robustness (1.7–5.2%) and mean body temperature levels (37.77±0.34 °C) as well as minima and maxima (36–39 °C versus 35.5–41.9 °C, free-ranging cats) of three captive cats, resulting in a significant shift towards a decrease in amplitude.     

Daily variation in body core temperature using radio-telemetry in aluminium industry shift-workers

The aim of this study was to investigate the diurnal variation in core temperature in aluminium shift-workers exposed to hot ambient conditions. Core temperature was continuously recorded via an ingestible radio-telemetry thermistor in 29 shift-workers. Data from the morning, afternoon and night shifts were aggregated for each participant to obtain 24-h recordings during work duties. Complete data were obtained from 10 participants. Results showed that body core temperatures recorded in the afternoon (from 12:00 h to 20:00 h) were significantly higher (P<0.05) than in the late evening, night and early morning (from 21:00 h to 08:00 h). In addition, core temperature displayed a circadian variation with a mesor of 37.45 (±0.19) °C, an amplitude of 0.23 (±0.12) °C and an acrophase at 16:36 h (±3:37 h). The peak values of core temperature recorded at each hour of the day on the work site followed the same pattern with an acrophase in the early afternoon. In summary, our data showed that shift-workers present higher core temperatures in the afternoon than in the morning or during the night. In addition, it was not the work duration but the hour-of-day that triggered the variation in core temperature. This result partly explains previous observations that workers under heat stress have a higher probability of heat illness during daytime shifts than during the night shift, and suggests that special care should be given to the afternoon shift and to the end of the morning shift.     

Diurnal pollen tube growth rate is slowed by high temperature in field-grown Gossypium hirsutum pistils

For Gossypium hirsutum pollination, germination, and pollen tube growth must occur in a highly concerted fashion on the day of flowering for fertilization to occur. Because reproductive success could be influenced by the photosynthetic activity of major source leaves, we hypothesized that increased temperatures under field conditions would limit fertilization by inhibiting diurnal pollen tube growth through the style and decreasing subtending leaf photosynthesis. To address this hypothesis, G. hirsutum seeds were sown on different dates to obtain flowers exposed to contrasting ambient temperatures while at the same developmental stage (node 8 above the cotyledons). Collection and measurement were conducted at 06:00, 09:00, 12:00, 15:00, and 18:00 h on August 4 (34.6 °C maximum air temperature) and 14, 2009 (29.9 °C maximum air temperature). Microclimate measurements included photosynthetically active radiation, relative humidity, and air temperature. Pistil measurements included pistil surface temperature, pollen germination, pollen tube growth through the style, fertilization efficiency, fertilized ovule number, and total number of ovules per ovary. Subtending leaf measurements included leaf temperature, photosynthesis, and stomatal conductance. Under high temperatures the first measurable pollen tube growth through the style was observed earlier in the day (12:00 h) than under cooler conditions (15:00 h). Also, high temperature resulted in slower pollen tube growth through the style (2.05 mm h⁻¹) relative to cooler conditions (3.35 mm h⁻¹), but there were no differences in fertilization efficiency, number of fertilized ovules, or ovule number. There was no effect of sampling date on diurnal photosynthetic patterns, where the maximum photosynthetic rate was observed at 12:00 h on both dates. It is concluded that, of the measured physiological and reproductive processes, pollen tube growth rate showed the greatest sensitivity to high temperature under field conditions.     

Evaporative water loss and energy metabolic in two small mammals,voles (Eothenomys miletus) and mice (Apodemus chevrieri), in Hengduan mountains region

Evaporative water loss (EWL) and energy metabolism were measured at different temperatures in Eothenomys miletus and Apodemus chevrieri in dry air. The thermal neutral zone (TNZ) of E. miletus was 22.5–30 °C and that of A. chevrieri was 20–27.5 °C. Mean body temperatures of the two species were 35.75±0.5 and 36.54±0.61 °C. Basal metabolic rates (BMR) were 1.92±0.17 and 2.7±0.5 ml O₂/g h, respectively. Average minimum thermal conductance (C_m) were 0.23±0.08 and 0.25±0.06 ml O₂/g h °C. EWL in E. miletus and A. chevrieri increased with the increase in temperature; the maximal EWL at 35 °C was 4.78±0.6 mg H₂O/g h in E. miletus, and 5.92±0.43 mg H₂O/g h in A. chevrieri. Percentage of evaporative heat loss to total heat production (EHL/HP) increased with the increase in temperature; the maximal EHL/HP was 22.45% at 30 °C in E. miletus, and in A. chevrieri it was 19.96% at 27.5 °C. The results may reflect features of small rodents in the Hengduan mountains region: both E. miletus and A. chevrieri have high levels of BMR and high levels of total thermal conductance, compared with the predicted values based on their body masses, while their body temperatures are relatively low. EWL plays an important role in temperature regulation.     

The extraction process optimization and physicochemical properties of polysaccharides from the roots of Euphorbia fischeriana

Response surface methodology (RSM) was used to determine the optimum extraction conditions for polysaccharides (EFP) from the roots of Euphorbia fischeriana. A Box-Behnken design (BBD) with four independent variables was investigated, such as extraction temperature (°C), water/solid ratio, extraction number (n), and extraction time (h). The results indicated optimum extraction conditions were extraction temperature of 97 °C, water/solid ratio of 9:1, extraction number of 2 and extraction time of 2.4 h, respectively. Under these conditions, the experimental value was 24.6 ± 0.62, which was well in close agreement with value predicted by the model. The preliminary chemical analysis of EFP revealed the EFP contained 25.43% polysaccharides, 20.42% uronic acids, 2.54% sulfate radical and 23.41% proteins. And the neutral polysaccharides were mainly composed of glucose, arabinose, rhamnose, galactose, xylose, mannose in the ratio of 21:8:5:3:1:1.     

Leptin and leptin receptor genetic variants associate with habitual physical activity and the arm body composition response to resistance training

Purpose

We investigated the influence of Leptin (LEP) and leptin receptor (LEPR) SNPs on habitual physical activity (PA) and body composition response to a unilateral, upper body resistance training (RT) program.

Methods

European-derived American volunteers (men = 111, women = 131, 23.4 ± 5.4 yr, 24.4 ± 4.6 kg·m^− 2) were genotyped for LEP 19 G>A (rs2167270), and LEPR 326 A>G (rs1137100), 668 A>G (rs1137101), 3057 G>A (rs1805096), and 1968 G>C (rs8179183). They completed the Paffenbarger PA Questionnaire. Arm muscle and subcutaneous fat volumes were measured before and after 12 wk of supervised RT with MRI. Multivariate and repeated measures ANCOVA tested differences among phenotypes by genotype and gender with age and body mass index as covariates.

Results

Adults with the LEP 19 GG genotype reported more kcal/wk in vigorous intensity PA (1273.3 ± 176.8, p = 0.017) and sports/recreation (1922.8 ± 226.0, p < 0.04) than A allele carriers (718.0 ± 147.2, 1328.6 ± 188.2, respectively). Those with the LEP 19 GG genotype spent more h/wk in light intensity PA (39.7 ± 1.6) than A allele carriers (35.0 ± 1.4, p = 0.03). In response to RT, adults with the LEPR 668 G allele gained greater arm muscle volume (67,687.05 ± 3186.7 vs. 52,321.87 ± 5125.05 mm³, p = 0.01) and subcutaneous fat volume (10,599.89 ± 3683.57 vs. − 5224.73 ± 5923.98 mm³, p = 0.02) than adults with the LEPR 668 AA genotype, respectively.

Conclusion

LEP19 G>A and LEPR 668 A>G associated with habitual PA and the body composition response to RT. These LEP and LEPR SNPs are located in coding exons likely influencing LEP and LEPR function. Further investigation is needed to confirm our findings and establish mechanisms for LEP and LEPR genotype and PA and body composition associations we observed.     

Modulatory Role of Ascorbic Acid on Behavioural Responses of Pigs Transported By Road during the Harmattan Season

Experiments were performed on adult local pigs with the aim of investigating the modulatory role of ascorbic acid (AA) on their behavioural responses to 4-h, road transportation during the harmattan season. Sixteen adult pigs administered with AA at the dose of 250 mg/kg dissolve in sterile water served as experimental animals, and 13 others administered with sterile water were used as control animals. All the pigs were transported for 4-h at speed of 40-50 km/h covering a distance of 140 km. The behavioural activities were determined before and after road transportation. The behavioural activities were higher (P.     

The effect of thermopreference on circadian thermoregulation in sprague-dawley and fisher 344 rats

Interstrain differences in thermoregulation of rats are important in biomedical research because subtleties in thermoregulatory sensitivities may greatly affect data collected. Little is known regarding how individual rodent strains differentially utilize behavioral thermal preference to regulate core temperature (Tc). Sprague-Dawley (SD) and Fischer 344 (F344) rats are known to have differences in thermoregulation including heat tolerance and are useful models to study interstrain differences in thermoregulation. Adult male SD and F344 rats of similar body size were implanted with radiotelemetry thermoprobes (DSI) to measure Tc and MA and housed in either a longitudinal temperature gradient with an ambient temperature (Ta) range of ∼15–40 °C to measure selected Ta (STa) or control environment maintained at a Ta of 23 °C. When continuously monitored for 48 h, Tc and MA increased at night, while STa decreased, according to their normal circadian cycle in both strains. SD rats were more active than F344 rats throughout the circadian cycle (SD gradient: day=12.9±1.2 m/h, night=32.1±2.4 m/h; F344 gradient: day=4.1±0.6 m/h, night=16.8±1.8 m/h; p<0.05 interstrain and circadian effects). The STa of each strain was greater during the daytime (SD: 26.4±0.2 °C; F344: 27.8±0.3 °C) than at night (SD: 24.7±0.3 °C; F344: 25.7±0.3 °C) confirming past studies that thermopreference during the day and night is greater than standard room temperature (∼23 °C). Correlations between MA and Tc suggest that MA has a greater effect on Tc in the F344 but not the SD strain when housed in a temperature gradient. There were significant strain differences in Tc depending on whether rats were housed in a temperature gradient. That is, the control F344 rats had a lower Tc during the transition from dark to light compared to rats housed in a gradient. Tc of the SD strain was unaffected by housing in the gradient. Rats are typically housed at a standard room temperature of 23 °C. However, the results demonstrate that when given the opportunity to behaviorally thermoregulate in a temperature gradient, the F344 strain selects a warmer environment that affects the regulation of Tc. This may be important in the experimenters' choice of ambient temperatures to house and study rats and other rodents.     

Thermogenic characteristics and evaporative water loss in the tree shrew (Tupaia belangeri)

Thermogenic characteristics and evaporative water loss were measured at different temperatures in Tupaia belangeri. The thermal neutral zone (TNZ) of T. belangeri was 30–35 °C. Mean body temperature was 39.76±0.27 °C and mean body mass was 100.86±9.09 g. Basal metabolic rate (BMR) was 1.38±0.03 ml O₂/g h. Average minimum thermal conductance (C_m) was 0.13±0.01 ml O₂/g h °C. Evaporative water loss in T. belangeri increased when the temperature rose; the maximal evaporative water loss was 3.88±0.41 mg H₂O/g h at 37.5 °C. The results may reflect features of small mammals in the sub-tropical plateau region: T. belangeri had high basal metabolic rate and high total thermal conductance, compared with the predicted values based on their body mass whilst their body temperatures are relatively high; T. belangeri has high levels of evaporative water loss and poor water-retention capacity. Evaporative water loss plays an important role in temperature regulation.     

Body temperature variation of free-ranging and captive southern brown bandicoots Isoodon obesulus (Marsupialia: Peramelidae)

To investigate patterns of thermoregulation in free-ranging and captive southern brown bandicoots Isoodon obesulus, we measured abdominal body temperature (T_b) of five free-ranging bandicoots over 42 days using implanted data loggers and T_b of three captive bandicoots over 3 months using implanted temperature-sensitive radio transmitters. Bandicoots in the wild had a mean T_b of 36.5±1.0 °C (range 33.4–39.8 °C) and showed a pronounced nychthemeral pattern with two distinct temperature phases. T_b increased at 13:30±2.6 h each day and remained high for 10.65±2.07 h, suggesting a crepuscular and early evening activity pattern. Daily T_b variation of I. obesulus would save considerable energy by reducing daytime thermoregulatory costs in the wild. Captive bandicoots had a similar mean body temperature (36.9±0.2°C) and range (33.0–39.9°C) as free-ranging bandicoots. However, the nychthemeral T_b pattern of captive bandicoots was different from free-ranging bandicoots, with a less pronounced daily cycle and the nocturnal rise in T_b occurring mainly at sunset and the daily decline occurring mainly at dawn.     

Cryopreservation of canine epididymal sperm using ACP-106c and TRIS

The objective was to cryopreserve sperm recovered from the canine epididymal cauda immediately after an orchiectomy. The sperm was stored for 12 h at 4 °C using ACP-106c and TRIS as extenders. Sixty adult male dogs were used. The testis–epididymis complex (TEC) was removed, immersed in 0.9% saline and transported to the laboratory. The 60 TEC were divided into groups according to the 4 °C cooling time (0 h or 12 h) and according to the extender used for sperm recovery (ACP-106c or TRIS), forming 4 experimental groups: G0h-ACP, G12h-ACP, G0h-TRIS and G12h-TRIS. The sperm were recovered from the epididymal cauda using the retrograde flow technique. Next, 1.0 mL of ACP-106c or 1.0 mL of TRIS (preheated to 37 °C for 5 min) was added to the sperm of each epididymis. One week later, the sperm was thawed at 37 °C for 1 min, and its morphology, functionality and total and progressive sperm motilities were analyzed. Other parameters were obtained by Computer Assisted Semen Analysis (CASA). The data were submitted to multivariate analysis of variance (MANOVA) (P < 0.05). The total motility values were 52.17 ± 1.78 and 49.8 ± 1.93 for groups G0h-ACP and G12h-ACP and 50.7 ± 2.06 and 43.90 ± 2.51 for groups G0h-TRIS and G12h-TRIS, respectively. A decrease in total sperm motility was observed after 12 h of cooling for both extenders (P < 0.05). ACP-106c can be used as an extender for freezing canine epididymal sperm, and the freezing procedure must be performed immediately after sperm recovery.     

Heat tolerance, behavioural temperature selection and temperature-dependent respiration in larval Octopus huttoni

This study reports temperature effects on paralarvae from a benthic octopus species, Octopus huttoni, found throughout New Zealand and temperate Australia. We quantified the thermal tolerance, thermal preference and temperature-dependent respiration rates in 1-5 days old paralarvae. Thermal stress (1 °C increase h⁻¹) and thermal selection (∼10-24 °C vertical gradient) experiments were conducted with paralarvae reared for 4 days at 16 °C. In addition, measurement of oxygen consumption at 10, 15, 20 and 25 °C was made for paralarvae aged 1, 4 and 5 days using microrespirometry. Onset of spasms, rigour (CT_max) and mortality (upper lethal limit) occurred for 50% of experimental animals at, respectively, 26.0±0.2 °C, 27.8±0.2 °C and 31.4±0.1 °C. The upper, 23.1±0.2 °C, and lower, 15.0±1.7 °C, temperatures actively avoided by paralarvae correspond with the temperature range over which normal behaviours were observed in the thermal stress experiments. Over the temperature range of 10 °C-25 °C, respiration rates, standardized for an individual larva, increased with age, from 54.0 to 165.2 nmol larvae⁻¹ h⁻¹ in one-day old larvae to 40.1-99.4 nmol h⁻¹ at five days. Older larvae showed a lesser response to increased temperature: the effect of increasing temperature from 20 to 25 °C (Q₁₀) on 5 days old larvae (Q₁₀=1.35) was lower when compared with the 1 day old larvae (Q₁₀=1.68). The lower Q₁₀ in older larvae may reflect age-related changes in metabolic processes or a greater scope of older larvae to respond to thermal stress such as by reducing activity. Collectively, our data indicate that temperatures >25 °C may be a critical temperature. Further studies on the population-level variation in thermal tolerance in this species are warranted to predict how continued increases in ocean temperature will limit O. huttoni at early larval stages across the range of this species.     

Effect of storage temperature on survival and infectivity of Steinernema rarum (OLI strain) (Rhabditida: Steinernematidae)

Nematode strains of the entomopathogenic family Steinernematidae differ in their ability to infect insects at different temperatures. Survival and infectivity of infective juveniles (IJs) of Steinernema rarum (OLI) were studied after their storage at 23 ± 2 °C and at 5 ± 1 °C. Survival at 23 ± 2 °C was always above 95%. At 5 ± 1 °C, survival decreased at week 5, but infectivity did the same after week 2. Unlike other steinernematids, both infectivity and survival of IJs would be higher for S. rarum (OLI) when stored at 23 ± 2 °C.     

Sun angle time windows for absconding by the dwarf honeybee, Apis florea

In Asia, the red dwarf honeybee, Apis florea, is notorious for its absconding habit. Interestingly, such colonies show a bimodal frequency distribution about a noonday lull throughout the year. Because slight errors in reading the relative position of the sun near its zenith results in very large orientation errors in the waggle dances of other honeybees in the tropics, we postulated that the frequency distribution of absconding in the red dwarf honeybee relative to local clock time could be explained in similar fashion. The frequency distribution of absconding by the red dwarf honeybee with respect to time was found to be bimodal with a pronounced lull at noonday, which in turn is related to the altitude angle of the sun. So, these bees largely avoid flying off between 12:00 h and 13:00 h on the one hand and that their preferred departure angle of the sun is between 55° and 65° on the other. Given the difficulties of taking an accurate reading of the sun at angles ±6° of the sun's zenith (resulting in a 1 h loss around noon) and the 2 h required to reach consensus over the final direction to be flown, the bees are simply left with two time windows, morning and afternoon, in which to abscond and, indeed some 90% of the red dwarf honeybee colonies do so. The noonday lull is not associated with high temperatures for any given day. Absconding is not inhibited by high temperatures.     

Metabolism,thermoregulation and evaporative water loss in the Chaotung Vole (Eothenomys olitor) in Yunnan-Kweichow Plateau in summer

Proper adjustment of thermoregulatory mechanisms ensures the survival of mammals when they are subjected to seasonal changes in their natural environment. To understand the physiological and ecological adaptations of Eothenomys olitor, we measured their metabolic rate, thermal conductance, body temperature (T_b) and evaporative water loss at a temperature range of 5–30 °C in summer. The thermal neutral zone (TNZ) of E. olitor was 20–27.5 °C, and the mean body temperature was 35.81±0.15 °C. Basal metabolic rate (BMR) was 2.81±0.11 ml O₂/g h and mean minimum thermal conductance (C_m) was 0.18±0.01 ml O₂/g h °C. Evaporative water loss (EWL) in E. olitor increased when the ambient temperature increased. The maximal evaporative water loss was 6.74±0.19 mg H₂O/g h at 30 °C. These results indicated that E. olitor have relatively high BMR, low body temperature, low lower critical temperature, and normal thermal conductance. EWL plays an inportant role in temperature regulation. These characteristics are closely related to the living habitat of the species, and represent its adaptive strategy to the climate of the Yunnan-Kweichow Plateau, a low-latitude, high-altitude region where annual temperature fluctuations are small, but daily temperature fluctuations are greater.