Thermoregulatory plasticity in free-ranging vervet monkeys,Chlorocebus pygerythrus

We used implanted miniature data loggers to obtain the first measurements of body temperature from a free-ranging anthropoid primate. Vervet monkeys (Chlorocebus pygerythrus) living in a highly seasonal, semi-arid environment maintained a lower mean 24-h body temperature in winter (34.6 ± 0.5 °C) than in summer (36.2 ± 0.1 °C), and demonstrated increased heterothermy (as indexed by the 24-h amplitude of their body temperature rhythm) in response to proximal environmental stressors. The mean 24-h amplitude of the body temperature rhythm in summer (2.5 ± 0.1 °C) was lower than that in winter (3.2 ± 0.4 °C), with the highest amplitude for an individual monkey (5.6 °C) recorded in winter. The higher amplitude of the body temperature rhythm in winter was a consequence primarily of lower 24-h minimum body temperatures during the nocturnal phase, when monkeys were inactive. These low minimum body temperatures were associated with low black globe temperature (GLMM, β = 0.046, P < 0.001), short photoperiod (β = 0.010, P < 0.001) and low rainfall over the previous 2 months, which we used as a proxy for food availability (β = 0.001, P < 0.001). Despite the lower average winter minimum body temperatures, there was no change in the lower modal body temperature between winter and summer. Therefore, unlike the regulated physiological adjustments proposed for torpor or hibernation, these minimum winter body temperatures did not appear to reflect a regulated reduction in body temperature. The thermoregulatory plasticity nevertheless may have fitness benefits for vervet monkeys.     

Change in overwintering mechanism of the Cucujid beetle, Cucujus clavipes

Overwintering larvae of the Cucujid beetle, Cucujus clavipes, were freeze tolerant, able to survive the freezing of their extracellular body fluids, during the winter of 1978–1979. These larvae had high levels of polyols (glycerol and sorbitol), thermal hysteresis proteins and haemolymph ice nucleators that prevented extensive supercooling (the supercooling points of the larvae were ? 10°C), thus preventing lethal intracellular ice formation. In contrast, C. clavipes larvae were freeze suspectible, died if frozen, during the winter of 1982–1983, but supercooled to ～ ? 30°C. The absence of the ice nucleators in the 1982–1983 larvae, obviously essential in the now freeze-susceptible insects, was the major detected difference in the larvae from the 2 years. However, experiments in which the larvae were artifically seeded at ? 10°C (the temperature at which the natural haemolymph ice nucleators produced spontaneous nucleation in the 1978–1979 freeze tolerant larvae) demonstrated that the absence of the ice nucleators was not the critical factor, or at least not the only critical factor, responsible for the loss of freeze tolerance in the 1982–1983 larvae. The lower lethal temperatures for the larvae were approximately the same during the 2 winters in spite of the change in overwintering strategy.     

Population dynamics, growth and reproduction of Corophium insidiosum (Crustacea: Amphipoda) at low salinities in Monolimni lagoon (Evros Delta, North Aegean Sea)

Distribution, population dynamics, growth and aspects of reproductive biology of Corophium insidiosum were investigated in Monolimni lagoon. Samples were collected in July 1997 (at 30 psu S) and during February 1998–May 1999 (at 0.1–5.7 psu S). Corophium insidiosumwas almost exclusively found in the outer part of the lagoon, which showed a higher water renewal rate. Population density gradually decreased during winter and spring, when salinity was lower than 1 psu and the amphipod finally vanished from the lagoon. Salinity increase during summer (1.2–5.7 psu) was followed by the re-occurrence of C. insidiosum with a time lag of 2–3 months. Population density increased in autumn and peaked in early winter at salinities 1.6–4.2 psu. Three cohorts appeared in the population during September 1998–March 1999. Breeding activity peaked in early autumn (14–21?°C, 4 psu S) and ceased after December (2–6.5?°C, ¡1.5 psu S). The preponderance of females in the large size classes resulted in a female- biased sex ratio in the whole population. The population showed a growth rate of 7.5–11.2 μm d^?1 being faster in autumn (9–21?°C, 3–4 psu S) than in winter (2–12?°C, 0.2–3 psu). An exponential relation existed between body length and cephalic length or dry body weight, while brood size was directly related to body length. Mean brood size was small (4.96 early embryos) and egg loss during development high (53%), possibly as a consequence of low salinities.     

The influence of temperature,sexual condition,and season on the metabolic rate of the lizardPsammodromus hispanicus

Summary Male and femalePsammodromus hispanicus from southern Europe were acclimated to four seasonal conditions of photoperiod and night time temperature. During the dark period, the lizards' body temperatures fell to ambient air temperature but during the light period the lizards were allowed to thermoregulate behaviourally and at such times the lizards' mean body temperature varied from 29.0°C to 32.6°C. The resting metabolic rate of these lizards was measured in 5°C steps from 5°C to 30°C or 35°C. Sexual condition had little effect on resting metabolic rate, but at low temperatures lizards acclimated to winter or spring seasonal conditions had lower resting metabolic rates than those acclimated to summer or autumn conditions. At temperatures above 20°C seasonal acclimation had no effect on resting metabolic rate. It is considered that the reduction in low temperature metabolic rate in spring and winter is induced by low night time temperatures and serves to conserve energy during those seasons when lizards must spend long periods at low temperature without being able to feed.     

Seasonal acclimatization in metabolic rate of the fan-fingered gecko,Ptyodactylus hasselquistii (Reptilia: Gekkonidae)

The resting metabolic rate of the fan-fingered gecko Ptyodactylus hasselquistii of various body masses was determined in relation to ambient temperatures ranging from 20 to 35°C during winter and summer acclimatization. Oxygen consumption (ml g⁻¹ h⁻¹) decreased with increasing mass at each temperature. The intraspecific exponents of body mass in relation to metabolic rate ranged from 0.62 to 0.79. Winter-acclimatized geckos had significantly lower metabolic rates than summer-acclimatized geckos at different temperatures, especially at low temperature (20°C). The pattern of acclimatization exhibited by P. hasselquistii may conserve energy during inactivity in winter and make activity more easily achieved during active seasons.     

Temperature effects on development ofOrius tantillus (Het.: Anthocoridae), A predator ofThrips palmi (Thys.: Thripidae)

To explore the possibility of usingOrius tantillus (Motschulsky) as a control agent againstThrips palmi Karny in greenhouses in Japan during the winter months, the effects of temperature on the development of eggs and nymphs of this predator were determined by rearing individuals under eight constant temperatures ranging from 17.5–35.0°C. Estimates of lower developmental threshold temperatures for eggs, male nymphs and female nymphs were 13.7°C, 11.9°C and 13.4°C, respectively. These estimates were lower than the average winter temperature at night in greenhouses in Japan, suggesting thatO. tantillus could possibly be used for the control ofT. palmi in such greenhouses. Thermal constants were estimated at 52.6, 185.2 and 153.8 degree days for eggs, male nymphs and female nymphs, respectively. Egg survival at temperatures between 20°C and 30°C was higher (p=0.05) than at 17.5°C.     

Variation in the content of free amino acids in body fluids of freshwater mollusk Lymnaea stagnalis during seasonal adaptation to low positive temperatures

The effect of autumn and winter decrease in environmental temperature on the content of free amino acids in body fluids has been studied in freshwater snail Lymnaea stagnalis. In autumn, when temperature drops to 4 and 0°C, the highest increase in alanine concentration was observed and its pool was almost three times that in summer. A less pronounced accumulation of glutamate, glycine, histidine, and serine was observed in the same temperature range. Cysteine was detected at 0°C. The accumulation of essential amino acids methionine, leucine, isoleucine, tyrosine, and phenylalanine took place at 0°C, while only traces of these amino acids were detectable at 4°C. At the same time, free lysine undetectable in summer has been revealed in autumn at 4°C and its concentration increased as temperature decreased to 0°C. In winter, when the mollusks were hypermetabolic for 2.5 months, the pools of all amino acids decreased 4–8 times, while essential amino acids (except lysine) were undetectable. The involvement of alanine and, possibly, lysine in L. stagnalis adaptation to near-zero temperature is proposed.     

The daily,weekly, and seasonal cycles of body temperature analyzed at large scale

ABSTRACT

We performed large-scale analyses of circadian and infradian cycles of human body temperature, focusing on changes over the day, week, and year. Temperatures (n= 93,225) were collected using temporal artery thermometers from a Boston emergency department during 2009–2012 and were statistically analyzed using regression with cyclic splines. The overall mean body temperature was 36.7°C (98.1°F), with a 95% confidence interval of 36.7–36.7°C (98.1–98.1°F) and a standard deviation of 0.6°C (1.1°F). Over the day, mean body temperature followed a steady cycle, reaching its minimum at 6:00–8:00 and its maximum at 18:00–20:00. Across days of the week, this diurnal cycle was essentially unchanged, even though activities and sleeping hours change substantially during the weekly cycles of human behavior. Over the year, body temperatures were slightly colder in winter than summer (~0.2°C difference), consistent with most prior studies. We propose these seasonal differences might be due to ambient effects on body temperature that are not eliminated because they fall within the tolerance range of the thermoregulatory system. Over the year, bathyphase (daily time of minimum temperature) appeared to parallel sunrise times, as expected from sunrise’s zeitgeber role in circadian rhythms. However, orthophase (daily time of maximum temperature) and sunset times followed opposite seasonal patterns, with orthophase preceding nightfall in summer and following nightfall in winter. Throughout the year, bathyphase and orthophase remained separated by approximately 12 h, suggesting this interval might be conserved. Finally, although 37.0°C (98.6°F) is widely recognized as the mean or normal human body temperature, analysis showed mean temperature was <37.0°C during all times of day, days of the week, and seasons of the year, supporting prior arguments that the 37.0°C standard has no scientific basis. Overall, this large study showed robust and consistent behavior of the human circadian cycle at the population level, providing a strong example of circadian homeostasis.     

Quantum Speciation of <Emphasis Type="Italic">Yersinia pestis</Emphasis> Plague Microbe in a Heteroimmune Environment: In the Populations of Hibernating Tarbagan Marmots (<Emphasis Type="Italic">Marmota sibirica</Emphasis>)

This review is devoted to the ecological mechanism for the transformation of the population of the psychrophilic saprozoobiont pseudotuberculosis microbe Yersinia pseudotuberculosis O:1b into the population of the obligate blood plague microbe Yersinia pestis in the host–parasite system of the marmot flea (Marmota sibirica–Oropsylla silantiewi). The correspondence of this mechanism to the evolutionary principle of quantum speciation has been shown. The most significant population–genetic microbial transformations took place in the populations of hibernating marmots. The main factor of rapid speciation was the heterothermic and, accordingly, heteroimmune state of host marmots during hibernation. During winter awakenings, the body temperature of marmots increases in an S-shaped manner from 5 to 37°C within a short period of time (from dozens of minutes to several hours). A drastic acceleration of metabolic and immune processes occurs in the temperature range of 20–30°C. Rapid adaptation to the “explosive” increase in the immune activity of the primary host (tarbagan marmot) during its regular winter awakenings was the essence of the process of Y. pestis speciation.     

The Influence of Temperature on Floral Initiation in the Olive

Floral initiation is completely inhibited when the olive is grown in a glasshouse at a minimum temperature of 16°C and a maximum temperature of 27°–30°C but occurs when it is grown at natural winter conditions in California. This study was undertaken to determine more specifically the temperature requirements for flowering and to show the relation of temperature treatment to hud development and floral initiation. Results of experiments performed with trees in containers grown at constant temperatures in controlled environment growth rooms show that the optimum temperature for flowering is 10°–13°C. Either higher (18°C) or lower (4°C) temperatures inhibit flowering completely. Morphological studies show that axis elongation and floral initiation occur in buds during temperature treatment at 10°C and 13°C but fail to occur during 4°C or 18°C treatments, or following these treatments when the temperature is raised to 21°C. When plants were exposed to 13°C for varying durations, it was found that no inflorescences formed after a 7.5 week exposure but that many formed after an 11-week exposure. A subsequent experiment showed that many more inflorescences formed after a 10-week exposure at 13°C than after 9 weeks exposure. Morphological changes in the bud seem to be associated with this increase in flowering affected by duration of treatment.     

Effects of body mass,temperature, and season on resting metabolism of the nocturnal gecko Hemidactylus flaviviridis

Abstract

The resting metabolic rate (RMR) of Hemidactylus flaviviridis was measured at different temperatures from 20 to 35°C during winter and summer acclimatization. The mass exponent b values ranged between 0.67 and 0.72. Winter-acclimatized geckos of various body masses had significantly lower RMRs than summer-acclimatized geckos only at 20°C. It seems that low thermal sensitivity for summer–acclimatized group may facilitate activity during its active seasons, and high thermal sensitivity between 20 and 25°C for winter–acclimatized group may conserve energy during inactivity in winter.     

Effects of salinity and cyclic temperature on survival of two sympatric species of grass shrimp (Palaemonetes), and their relationship to natural distributions

Survival and respiration of the grass shrimp Palaemonetes pugio Holthuis and P. vulgaris (Say) from the Newport River estuary were measured after exposure to cyclic and constant winter temperatures, to rapid decreases in temperature, and to various temperature-salinity combinations. Both species were subjected to nine temperature-salinity combinations including temperature regimes of cyclic 7–13°C, constant 7° and 10°C, and salinities of 5, 20, and 35%.. Based on the laboratory and field results, the differences in physiological tolerance to winter temperatures and salinities were examined in relation to habitat partitioning by these sympatric species.Survival after continuous exposure to cyclic temperature regimes at medium to high salinities was similar to that observed for comparable constant temperatures; however, at low salinities mortality was significantly lower under the cyclic regime than under either constant regime. This suggests that cyclic temperatures may be detrimental in combination with some other stress. A rapid, transient decrease in temperature from either 7° or 10°C to 2°C had no measurable effect on survival or rate of oxygen consumption at any temperature-salinity acclimation. Neither salinity (except in areas intermittently subjected to salinities below 3 %.) nor winter temperatures appear to affect habitat partitioning in grass shrimp.     

Seasonal variations in basal metabolic rate, lower critical temperature and responses to temporary starvation in the arctic fox (Alopex lagopus) from Svalbard

Metabolic rates of four resting, post-absorptive male adult summer- and winter-adapted captive arctic foxes (Alopex lagopus) were recorded. Basal metabolic rates (BMR) varied seasonally with a 36% increase from winter to summer, while body mass was reduced by 17% in the same period. The lower critical temperature (T _1c) of the winter-adapted arctic fox was estimated to −7°C, whereas T _lc during summer was 5°C. The similarity of these values, which are much higher than hitherto assumed (e.g. Scholander et al. 1950b), is mainly due to a significantly (P<0.05) lower BMR in winter than in summer. Body core (stomach) temperature was stable, even at ambient temperatures as low as −45°C, but showed a significant (P<0.05) seasonal variation, being lower in winter (39.3±0.33°C) than in summer (39.8±0.16°C). The thermal conductivity of arctic fox fur was the same during both seasons, whereas the thermal conductance in winter was lower than in summer. This was reflected in an increase in fur thickness of 140% from summer to winter, and in a reduced metabolic response to ambient temperatures below T _lc in winter. Another four arctic foxes were exposed to three periods of forced starvation, each lasting 8 days during winter, when body mass is in decline. No significant reduction in mass specific BMR was observed during the exposure to starvation, and respiratory quotient was unchanged at 0.73±0.02 during the first 5 days, but dropped significantly (P<0.05) to 0.69±0.03 at day 7. Locomotor activity and body core (intraperitoneal) temperature was unaltered throughout the starvation period, but body mass was reduced by 18.5±2.1% during these periods. Upon re-feeding, locomotor activity was significantly (P<0.05) reduced for about 6 days. Energy intake was almost doubled, but stabilised at normal levels after 11 days. Body mass increased, but not to the level before the starvation episodes. Instead, body mass increased until it reached the reduced body mass of ad libitum fed control animals. This indicates that body mass in the arctic fox is regulated according to a seasonally changing set point.     

Shifts in thermal preference of introduced Asian house geckos (Hemidactylus frenatus) in temperate regions of southeastern Australia

Despite its tropical origin, the Asian house gecko (Hemidactylus frenatus) is currently invading higher latitudes around the world. In this study, we investigated whether the introduced geckos in the subtropical/temperate region of southeastern Australia have shifted their thermal biology to cope with colder temperatures. In the lab, we measured the body temperatures of geckos from Thailand and Australia in a cost-free thermal gradient. Native H. frenatus from Thailand displayed a diel pattern of thermoregulation. Geckos maintained higher body temperatures during mid-afternoon and at dusk but selected cooler temperatures during the night. Introduced geckos showed a similar pattern of thermoregulation, but selected lower body temperatures in summer (mean = 28.9 °C) and winter (mean = 25.5 °C) than native geckos (mean = 31.5 °C). While the Asian house geckos from Thailand did not alter their body temperatures after feeding, their conspecifics from southeastern Australia selected body temperatures that were 1.6–3.1 °C higher after feeding. In conclusion, our study shows that invasive house geckos in Australia have shifted their preferred body temperatures downwards relative to their native conspecifics in Thailand, presumably as a result of plasticity or natural selection. Our findings suggest that these tropical geckos have adapted to colder regions, and thus, they may spread much further than expected for a tropical ectotherm.     

Thermal biology of the Central Asian blunt-nosed viper (Macrovipera lebetina turanica) from Nuratau Crest and the Chernov blunt-nosed viper (Macrovipera lebetina černovi) from Western Kysylkum

The ecology of the Central Asian blunt-nosed viper (Macrovipera lebetina turanica) inhabiting the Nuratau Crest of Uzbekistan is described. The temperature conditions of the environment and the spatialtemporal structure of the viper activity are represented, which made it possible to find some of thermobiological characteristics. The temperature diapason of full activity of this viper constitutes approximately 17–34°C. The temperature of thermostabilization is in the range of 26–31°C, nocturnal temperatures are elevated from 9–15°C to 18–23°C in spring and summer, respectively, and diurnal body temperatures are decreased from 18–22°C to 10–15°C. Feeding and digestion are normal in blunt-nosed vipers at 25°C, which is below the diurnal temperature variation. In spring, the light phase duration is rapidly increased from 3–6 h to 14 h or more. This length of time and the large diurnal variation in the body temperature from 18°C to 20–22°C facilitate active and efficient coupling. Later, the diurnal body temperature is decreased to 13–18°C, which facilitates successful recovery in males and pregnancy in females. Plots for the average viper body temperature in different seasons are represented. The thermobiological characteristics of the bluntnosed viper of Macrovipera lebetina ěrnovi are similar to M. l. turanica.     

The cultivation of oak seedlings inoculated with Tuber aestivum Vittad. in the boreal region of Finland

Despite recent findings, truffles are rarely found in Finland. In 2006, we began to explore the cultivation potential of Tuber aestivum/uncinatum in Finland. In 2006–2008, roughly 1,200 Quercus robur seedlings and 200 Q. pubescens seedlings were planted in 20 orchards. We aimed to challenge the Southern European (France) tree provenances of oak seedlings in a boreal climate. Additional winter coverings made up of fabric or plastic and twigs prevented the seedlings’ mortality even when the air temperature was below ?30 °C during the second winter. The results showed that the top soil temperature at 15 cm depth has to be above ?5 °C to guarantee the survival of seedlings. Q. pubescens was more sensitive to low soil temperatures than Q. robur. Morphological and PCR analysis of root samples collected over 2007–2010 confirmed the presence of T. aestivum in all orchards despite unfavorable temperatures during the winter time. The first T. aestivum sporocarps were found under Q. robur in October 2012 in the orchards established in 2006 on old agricultural land, showing truffle cultivation to be successful in the boreal climate.     

Enhanced granulocyte phagocytosis at low winter temperature and high summer temperature in the tench (Tinca tinca L.)

Tench were captured in summer and winter when water temperature was 30 ± 3°C and 12 ± 2°C, respectively. Blood granulocytes were assayed for mobility capacity and phagocytic and microbicide capability to Candida albicans at 22°C and 30°C in summer and at 22°C and 12°C in winter. The results showed that tench granulocytes were more active in winter than in summer, and that phagocytic function was greatest at the seasonal temperature (30°C in summer and 12°C in winter) with respect to 22°C. This study suggests the importance of seasonally in the study of temperature effects on fish phagocyte function.     

Effects of different cold-air exposure intensities on the risk of cardiovascular disease in healthy and hypertensive rats

Ten-week-old male Wistar rats (systolic blood pressure, 106–116 mmHg; body weight, 300–320 g) and spontaneously hypertensive rats (systolic blood pressure, 160–176 mmHg; body weight, 210.9–244.9 g) were used as healthy and hypertensive subjects to determine the effects of varying degrees of cold-air exposure in a climate chamber box. The three cold-air ranks were cold air I [minimum temperature (TMIN) 6.4 °C, ↓?T₄₈ 8.6 °C], cold air II (TMIN 3.8 °C, ↓?T₄₈ 11.2 °C), and cold air III (TMIN ?0.3 °C, ↓?T₄₈ 15.3 °C), as established from the cold-air data of Zhangye City, China. Each cold-air rank consisted of a temperature drop and a temperature increase with the same initial and terminal temperatures (15 °C). After cold-air exposure, the risk factors for cardiovascular disease (CVD) such as systolic blood pressure, whole blood viscosity (10/s and 150/s), plasma fibrinogen, and blood lipids of the rats were determined. The results indicated that the CVD risk factors of the healthy and hypertensive rats increased significantly with cold-air exposure intensities. The increase in systolic blood pressure was greater during temperature drops, whereas the increases in whole blood viscosity and plasma fibrinogen were greater after cold-air exposure. The effects of cold-air exposure on the CVD risk factors of healthy rats, particularly the systolic blood pressure, whole blood viscosity (150/s), and LDL/HDL, were greater than those in hypertensive rats. In conclusion, CVD risk may increase with cold-air ranks. Blood pressure-induced CVD risk may be greater during cold-air temperature drop, whereas atherosclerosis-induced CVD risk may be greater after cold-air exposure. The effect of cold air on the CVD risk factors in healthy subjects may be more significant than those in hypertensive subjects.     

Energy Allocation Changes in Overwintering Adults of the Common Pistachio Psylla, Agonoscena pistaciae Burckhardt & Lauterer (Hemiptera: Psyllidae)

The common pistachio psylla, Agonoscena pistaciae Burckhardt & Lauterer (Hemiptera: Psyllidae), is known as the key pest of pistachio orchards in Iran. This pest passes the winter as adults. In this study, energy allocation changes in relation to ambient temperature were investigated in field-collected adults by measuring total body sugar, trehalose, glucose, sorbitol, myoinositol, glycogen, lipid, and protein contents. Glycogen content decreased with decrease in ambient temperature. The decrease in glycogen content was proportional to the increase in total body sugar, trehalose, myoinositol, and sorbitol contents. In January, with mean ambient temperature of 5.4°C, glycogen content was at the lowest level, whereas total body sugar, trehalose, glucose, and sorbitol were at the highest level. Total body sugar, trehalose, myoinositol, and sorbitol contents increased as temperature decreased from 22.7°C in October to 5.4°C in January. In conclusion, low molecular weight carbohydrates and polyols may play a role in winter survival and adaptation to cold of the common pistachio psylla by providing the required cryoprotection. Also, overwintering adults of the common pistachio psylla may store energy in the form of lipid for later utilization during the overwintering.     

Seasonal changes in entrainment cues for the circadian rhythm of the supratidal amphipod Talorchestia longicornis

The supratidal amphipod Talorchestia longicornis Say has a circadian rhythm in activity, in which it is active on the substrate surface at night and inactive in burrows during the day. The present study determined: (1) the circadian rhythms in individual versus groups of amphipods; (2) the range of temperature cycles that entrain the circadian rhythm; (3) entrainment by high-temperature cycles versus light?:?dark cycles, and (4) seasonal substrate temperature cycles. The circadian rhythm was determined by monitoring temporal changes in surface activity using a video system. Individual and groups of amphipods have similar circadian rhythms. Entrainment occurred only to temperature cycles that included temperatures below 20°C (10–20, 15–20, 17–19, 15–25°C) but not to temperatures above 20°C (20–25, 20–30°C), and required only a 2°C temperature cycle (17–19°C). Diel substrate temperatures were above 20°C in the summer and below 20°C during the winter. Upon simultaneous exposure to a diel high-temperature cycle (20–30°C) and a light?:?dark cycle phased differently, amphipods entrained to the light?:?dark cycle. Past studies found that a temperature cycle below 20°C overrode the light?:?dark cycle for entrainment. The functional significance of this change in entrainment cues may be that while buried during the winter, the activity rhythm remains in phase with the day?:?night cycle by the substrate temperature cycles. During the summer, T. longicornis switches to the light?:?dark cycle for entrainment, perhaps as a mechanism to phase activity precisely to the short summer nights.