Influence of acclimation temperature and season on acute temperature preference of adult mountain whitefish,Prosopium williamsoni

Synopsis Temperatures preferred by four groups of adult mountain whitefish, Prosopium williamsoni, collected in October before spawning, in December after spawning, in late winter, and in spring were determined in the laboratory in a horizontal gradient. Acute temperature preference based on fish tested soon after capture and final preferendum estimates were 12.8 and 17.7°C, respectively (pre-spawning), 9.6 and 11.9°C (post-spawning), 10.8 and 9.9°C (winter), and 16.4 and 16.3°C (spring). Seasonal influence on temperature preference was evident on the basis of differences in final preferenda, covariance analysis of responses of laboratory-acclimated fish, and temperature preference of fish held at ambient river temperatures. Fish of the post-spawning and winter groups preferred lower temperatures than did those of pre-spawning and spring groups. Temperatures preferred by pre-spawning fish were too high for embryo survival. Caution is necessary in predicting thermal preference on the basis of a sample collected at one time of year or stage of sexual development.     

Effect of long-term thermal acclimation on the electrical avoidance conditioning of fish

The learning behaviour and memory formation of ectotherms, especially of fish, depend significantly on the acclimation temperature. Although temperature is known to affect different physiological factors in the nervous system, the exact manner in which memory and learning are affected by these alterations is not clear. Large variations in the acclimation time before learning takes place, are striking. With regard to long-lasting compensatory changes in the polarity of membrane-bound neuronal gangliosides (1) and in the bio-electrical activity of the CNS (post-synaptic potential amplitudes (2)) following thermal acclimation it was of interest to investigate the time course of acclimation on the learning ability of fish subjected to a new environmental temperature.     

恒温和变温驯化对大蟾蜍蝌蚪热耐受性的影响

为了解大蟾蜍蝌蚪(Bufo gargarizans)的热适应性并验证最适性模型,将大蟾蜍蝌蚪分别在10、15、20℃和25℃4个不同恒温下及15.76-5.42℃的变温下驯养2周,利用温度梯度装置观察记录其最适温度、最高逃避温度和最高致死温度。结果表明,经过在10、15、20℃和25℃四个恒温及在15.76—5.42℃的变温下驯化,大蟾蜍蝌蚪的最适温度分别为(14.8±2.9),(17.2±3.8),(18.1±3.5),(19.6±2.5)和(15.8±2.2)℃;最高逃避温度分别为(27.6±1.9),(31.3±1.3),(32.5±0.8),(33.9±1.0)和(31.6±1.3)℃;最高致死温度分别为(32.9±1.6),(36.5±1.0),(37.9±0.9),(38.8±1.1)和(37.2±1.3)℃。驯化温度对大蟾蜍蝌蚪的最适温度、最高逃避温度和最高致死温度都有显著影响(P0.001)。驯化温度对大蟾蜍蝌蚪最适温度产生的影响比最高逃避温度和最高致死温度的小。温度的昼夜变化,都会呈现两峰或三峰分布,双峰环境实际上是具有同一标准误差的两个正常分布的混合体,这两个正常分布被一个峰间距所隔离。最适性模型预测:当呈双峰分布的温度的峰间距为17℃时,动物将出现3个适合度峰值。研究结果支持最适性模型。     

Effects of evolutionary thermal environment on temperature-preference relationships in fishes

Fishes exhibit a perplexing variety of temperature-preference relationships, ranging from positive to negative functions of acclimation temperature. However, these relationships tend to be consistent within species even across broad geographic ranges. We developed and tested an hypothesis that temperature-preference relationships are related to the amplitude of the annual thermal-cycle experienced by species during their recent evolutionary histories. Species experiencing annual cycles of relatively high amplitude (temperate species) were predicted to exhibit temperature-preference relationships that are positive functions of acclimation temperature. Those with low thermal amplitudes, such as cold stenotherms, or relatively high short-term amplitudes, such as tropical mesotherms, were predicted to exhibit relationships that are either independent or negative functions of acclimation temperature. This hypothesis was tested and strongly supported by a synthesis of studies from the literature. Of 42 species, for which data were available, 40 exhibited the class of temperature-preference relationships that we predicted on the basis of their thermal cycle. The concept of thermal guilds can be expanded by taking into consideration the capacity of fishes to adjust preferred temperatures through acclimation. This work shows the adaptive nature of temperature-preference behavior and may be useful for predicting general characteristics of temperature-preference relationships for the many species not yet examined in this regard.     

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.     

The effect of temperature and thermal acclimation on the sustainable performance of swimming scup

There is a significant reduction in overall maximum power output of muscle at low temperatures due to reduced steady-state (i.e. maximum activation) power-generating capabilities of muscle. However, during cyclical locomotion, a further reduction in power is due to the interplay between non-steady-state contractile properties of muscle (i.e. rates of activation and relaxation) and the stimulation and the length-change pattern muscle undergoes in vivo. In particular, even though the relaxation rate of scup red muscle is slowed greatly at cold temperatures (10°C), warm-acclimated scup swim with the same stimulus duty cycles at cold as they do at warm temperature, not affording slow-relaxing muscle any additional time to relax. Hence, at 10°C, red muscle generates extremely low or negative work in most parts of the body, at all but the slowest swimming speeds.Do scup shorten their stimulation duration and increase muscle relaxation rate during cold acclimation? At 10°C, electromyography (EMG) duty cycles were 18% shorter in cold-acclimated scup than in warm-acclimated scup. But contrary to the expectations, the red muscle did not have a faster relaxation rate, rather, cold-acclimated muscle had an approximately 50% faster activation rate. By driving cold- and warm-acclimated muscle through cold- and warm-acclimated conditions, we found a very large increase in red muscle power during swimming at 10°C. As expected, reducing stimulation duration markedly increased power output. However, the increased rate of activation alone produced an even greater effect. Hence, to fully understand thermal acclimation, it is necessary to examine the whole system under realistic physiological conditions.     

Critical thermal maxima and acclimation rate of the tropical guppy Poecilla reticulata

Tropical guppies, Poecilia reticulata, collected from the canal of La Laguna Los Patos were acclimated over a four-week period at local water temperatures of 24–33 °C to determine their critical thermal maxima (CTM) and death points (DP), as criteria of thermal tolerance. In addition, individual thermal tolerance times at a lethal temperature of 38.5 °C were measured over 12 days for upward acclimation from 24 to 30 °C and over 16 days for downward acclimation from 30 to 24 °C to determine acclimation rate just before and after changing the acclimation temperatures. The CTM ranged from 38.95 to 40.61 °C and the average DP varied from 41.22 to 42.86 °C. Positive relationships were apparent between thermal tolerance and acclimation temperatures, and thus heat tolerance criteria (CTM and DP) were significantly different among acclimation temperatures. Individual heat tolerance times increased most rapidly during the first 6 hours of upward acclimation after transfer from 24 to 30 °C, continued to increase another 5 days and fluctuated after initial acclimation was completed. The heat tolerance times of fish transferred from 30 to 24 °C declined steadily over times, reaching a minimum at 14–16 days after transfer.     

Effects of Parturition and Feeding on Thermal Preference of Atlantic Stingray, Dasyatis sabina (Lesueur)

Synopsis Temperature is the most important and least well documented environmental entity affecting reproduction and feeding of elasmobranch fishes, but it is unclear to what extent these fish may exploit behavioral thermoregulation to optimize physiological processes. Laboratory thermal preference determinations are important to understanding behavioral processes because they provide the vital quantitative link between environment, physiology, and adaptive behavior. Temperature preference data were collected on Atlantic stingrays, Dasyatis sabina (Lesueur) to assess the fishs’ ability to behaviorally optimize feeding and reproduction. Groups of male and pregnant female Atlantic stingrays exhibited statistically higher preferred median temperatures (26.2 and 26.1°C, respectively) than non-pregnant females (25.3°C; One-Way ANOVA on ranked data, F _[2,26] = 3.72, p=0.038). Median preferred temperatures in unfed stingrays of both genders ranged from 24.5 to 31.0°C, whereas, fed fish preferred temperatures between 23.5 and 27.5°C. Unfed stingrays preferred a median temperature of 24.5°C; however, after feeding fish preferred significantly warmer water temperatures of 25.7°C (Wilcoxon one-tail, matched-pairs, signed rank analysis; p<0.088). While overall differences were subtle, small preference adjustments can have important physiological consequences. For example, the 1°C increase seen in pregnant females over non-pregnant fish would reduce gestation time by as much as two weeks. Likewise, by moving to cooler water after feeding, stingrays may increase nutrient uptake efficiency by reducing evacuation rates. Our data indicate that movement and distribution of Atlantic stingrays are dictated, in part, by temperature effects on physiology.     

热驯化对鼎突多刺蚁热适应和运动行为的影响

为比较恒温和变温驯化对鼎突多刺蚁（Polyrhachis vicina Roger）热适应和运动行为的影响,将鼎突多翅蚁分别在15℃恒温和13.4～21.6℃变温下进行驯化,定量分析两种驯化温度对鼎突多翅蚁热适应和运动行为的影响.结果表明,恒温和变温驯化对鼎突多刺蚁的最适温度、逃避高温、运动中的停顿频率、疾跑速度、最大持续运动距离均有显著影响（p＜0.01）,而对逃避低温的影响不显著（p=0.343）;变温驯化后鼎突多刺蚁的最适温度仅有一个峰值,这不符合最适性模型的预测;恒温和变温驯化下鼎突多刺蚁的疾跑速度与最大持续运动距离都呈显著的正相关（分别为p=0.017和p＜0.001）,且经过变温驯化的鼎突多刺蚁的运动能力明显强于恒温驯化下个体的运动能力.     

Short-term thermal acclimation induces adaptive changes in the inner mitochondrial membranes of fish skeletal muscle

In the oxidative muscles (musculi laterales superficiales) of crucian carp Carassius carassius acclimated for 6 weeks to either 5 or 25° C, the volume density and the surface density of fibres per tissue did not differ significantly between the control and experimental groups. The correlation ratio (μ²) for these values was below 50, 39·3 and 43·9 respectively. After acclimation to 5° C, the surface density of outer mitochondrial membrane per fibre increased significantly from 0·93 to 1·23m² cm⁻³ in the summer population but dropped from 0·94 to 0·67 m² cm⁻³ in the winter population. The surface density of outer mitochondrial membrane per mitochondrion increased from 3·24 to 4·52 m² cm⁻³ in summer fish. After acclimation to 25° C, the surface density of inner mitochondrial membranes per muscle fibre decreased from 4·04 to 1·79 m² cm⁻³ in summer fish and from 3·86 to 1·07 m² cm⁻³ in winter fish. The surface density of inner mitochondrial membranes per mitochondrion increased from 14·17 to 15·60 m²cm⁻³ in summer fish but dropped from 13·91 to 10·67 m² cm⁻³ in winter fish. Correlation matrices demonstrate a negative correlation of the surface density of outer mitochondrial membrane per mitochondrion with the volume density of mitochondria per fibre and temperature, suggesting cold-induced proliferation of small mitochondria. It was concluded that short-term cold acclimation increased surface area of the inner mitochondrial membranes in summer fish.     

Ontogenetic changes in temperature preference of Atlantic cod

Final thermal preferendum ( T ) experiments were conducted in a horizontal thermal gradient tank from the beginning of August 2001 to mid‐November 2001 using Atlantic cod Gadus morhua from 6·5 to 79·0 cm fork length ( L _F). The value of T varied significantly ( P  < 0·005) with L _F( T  = 7·23–0·054 L _F), with smaller (younger) fish choosing higher temperatures than larger (older) fish. The preferendum varied from 6·9° C for fish of 6·5 cm to 3·0° C for those of 79·0 cm. Experiments comparing fish positions in the gradient tank between thermal gradients of 0·5–11·0 and 4·5–14·5° C demonstrated that fish positions were determined by temperature selection instead of undesirable tank effects. This study is the first to demonstrate the effect of ontogeny on temperature preferences of a marine fish species.     

Highly‐enhanced larval growth during the cold season mediated by the basking behavior of the butterfly Parnassius citrinarius (Lepidoptera: Papilionidae)

Some insect species are thought to grow quickly, even in low temperatures under natural conditions, presumably by conducting basking behaviors to use sunlight. However, whether basking behavior in fact enhances developmental speed and shortens the larval period in the field has not been determined. Moreover, few studies have examined whether basking is behavioral thermoregulation or simply the result of highly‐heterogeneous heat environments in the field. To examine these issues, we conducted field observations and laboratory experiments using larvae of Parnassius citrinarius Motschulsky, which mature within a short period after the thaw in early spring. First, body temperatures of larvae were measured under sunny and cloudy conditions. Second, larval preference for warmer locations was examined. Finally, we compared the developmental speed of larvae when they basked under field conditions and when did not bask in laboratory conditions under different air temperature regimes. Under sunny conditions, larval body temperature was substantially higher than either the temperature of the host plant or the air temperature, and was equivalent to the temperature of dead leaves, which the larvae used as basking sites. In contrast, no such tendency was observed under cloudy conditions. Larvae exhibited an exclusive preference for warmer locations. Moreover, in the field, despite the low ambient temperature, larvae grew much faster than those reared in the laboratory. These results imply that the basking behavior of P. citrinarius larvae is active thermoregulation to maintain high body temperatures in the cold season.     

The effects of thermal acclimation upon ion transport in erythrocytes

The different components of ⁸⁶Rb⁺ influx (a marker for K⁺ influx) were measured in erythrocytes of 10°C and 30°C-acclimated carp. Passive influx was similar in both acclimation groups and was stimulated by increased temperature. The active and facilitated components of ⁸⁶Rb⁺ influx plateaued above 15°C in 10°C-acclimated carp and above 25°C in 30°C-acclimated carp. The furosemide-sensitive component, an ill-defined facilitated mechanism, was particularly affected by high temperatures. The influx rates of each acclimation group at 50°C were almost identical but at higher temperatures, the influx rates for 30°C-acclimated carp were substantially greater than for the 10°C-acclimated fish.     

The effect of acclimation temperature and the removal of peripheral temperature receptors on body temperature preference in the cockroach, Periplaneta americana

1. 1.|Body temperature preferences were compared between cockroaches acclimated to different ambient temperatures and between 25°C acclimated cockroaches and cockroaches deprived of their peripheral temperature receptors.

2. 2.|Acclimation to 35°C resulted in a significantly higher mean body temperature and low body temperature selected compared with 25°C acclimated cockroaches.

3. 3.|Cockroaches deprived of their peripheral temperature receptors showed a significantly higher mean high body temperature selected when compared to normal 25°C acclimated cockroaches.

4. 4.|It is concluded that cockroach temperature regulation is more precise than expected and that central temperature receptors are the primary sensing elements for cockroach thermoregulation.

Resistance to thermal stress in adult Drosophila buzzatii: acclimation and variation among populations

Survival after heat stress was examined in adult Drosophila buzzatii from seven localities. Males and females were conditioned by a non-lethal high temperature before exposure to a severe thermal stress. Variable times elapsed between conditioning, either as adults or pupae, and exposure to the stress were used, and experimental times to the stress ranged from 2 to 96 hours. Survival after stress varied among populations, and differences generally were consistent across conditioning treatments and across experiments. Resistance to thermal stress was much higher following one conditioning bout 2–4 hours before exposure to a severe stress than when the time elapsed between conditioning and exposure was increased to 24 or more hours. Significantly more adults survived the stress if conditioned 4 days before exposure to the thermal stress, either as adults or as pupae, than if not conditioned. The rank order of resistance roughly followed that predicted from the climatic conditions of the localities of origin.