Background: The temperature preferences of cold-blooded animals are different for different groups of animals and are closely related to their evolutionary status and level of adaptive capabilities. The range of prefe...Background: The temperature preferences of cold-blooded animals are different for different groups of animals and are closely related to their evolutionary status and level of adaptive capabilities. The range of preferred temperatures for reptiles (28°C - 32°C) coincides with the zone of temperature-dependent increase in the rate of the M-cholinergic reaction in the brain, which was previously found in warm-blooded neurons. The growth of the M-cholinergic process contributes to the transition of adaptive behavior to a higher level. Of the cold-blooded, only reptiles actively use thermoregulatory behavior as a tool to achieve a temperature optimum. This paper is devoted to the study of the behavior of red-eared turtles aimed at reaching the range of preferred temperatures. Temperature conditions necessary for the survival of different groups of cold-blooded animals are compared and the reason for temperature preferences is discussed. Methods: The behavior of turtles was studied under conditions of variable solar radiation and in a 3-section terrarium with gradual temperature ranges: 23°C - 24°C;28°C - 31°C and 45°C - 50°C. Results: It was found that prolonged (up to 1.5 hours) heating at a temperature of 45°C - 50°C was the best way to achieve the preferred temperatures. This method of heating results in increasing the temperature of the shell to an average of 37°C, followed by a very slow decrease during 4 - 6 hours within the limits that closely coincided with the preferred level. Conclusion: The results obtained demonstrate that the main function of the turtle shell is to accumulate heat and keep it for a long time in a variable climate. The preferred temperature achieved in this case is necessary for the temperature-dependent transition of the rate of the M-cholinergic reaction in the brain to a higher level, which creates more significant adaptive capabilities. The temperature range of the M-cholinergic process has two inflection points at 27°C - 29°C and 34°C - 36°C. In accordance with these values, the temperature preferences of cold-blooded animals are divided into three groups: 0°C - 28°C (fish and amphibians);28°C - 32°C (reptiles) and 34°C - 36°C (dinosaurs). Different ranges of preferred temperatures correspond to three stages of adaptive development.展开更多
The main purpose of this study is to investigate temperature preference for habitat of three species of oceanic sea skaters, Halobates micans, H. germanus and H. sericeus. For each of the three species, we examined th...The main purpose of this study is to investigate temperature preference for habitat of three species of oceanic sea skaters, Halobates micans, H. germanus and H. sericeus. For each of the three species, we examined the relationship between population density and surface water and air temperatures in the sampling sites during three science cruises in the tropical to temperate zone of the Pacific Ocean. A higher density of H. micans was observed in sites with higher water and air temperatures at 28℃?- 30℃?than that at site with lower temperatures of 23℃?- 28℃. A higher density of H. germanus was observed in sites with extremely high temperatures of 29.6℃?and 30℃?than that in sites with moderately high temperatures of 28℃?- 29℃?in the Pacific Ocean, while a relatively high density was observed in sites with a wide range of temperatures from 24℃?- 30℃?in the southern hemisphere Pacific Ocean. The relatively low temperature preference of 23℃?- 28℃?exhibited by H. sericeus may be related to its size as the smallest among the three species and its relatively wide latitudinal distribution ranging up to 40?N.展开更多
The big-headed turtle Platysternon megacephalum is a stream-dwelling species whose ecology is poorly known. We carried out field and laboratory investigations to determine field body temperatures and thermal preferenc...The big-headed turtle Platysternon megacephalum is a stream-dwelling species whose ecology is poorly known. We carried out field and laboratory investigations to determine field body temperatures and thermal preference of this species. In the field, the body temperatures of the turtles conformed to the water temperature, with little diel variation in either summer or au- tumn. Over the diel cycle, the mean body temperatures ranged from 20.8℃ to 22.2℃ in summer and from 19.3℃ to 21.2℃ in autumn; the highest body temperatures ranged from 22.1℃ to 25.0℃ in summer and from 20.6℃ to 23.8℃ in autumn. In the laboratory, the preferred body temperature （Tp） was 25.3℃ Food intake was maximized at 24.0℃, whereas locomotor perfor- mance peaked at 30.0℃. Consequently, Tp was closer to the thermal optimum for food intake than for locomotion. Therefore, this freshwater turtle has relative low field body temperatures corresponding to its thermal environment. In addition, the turtle prefers low temperatures and has a low optimal temperature for food intake [Current Zoology 59 （5）： 626-632, 20＇13].展开更多
文摘Background: The temperature preferences of cold-blooded animals are different for different groups of animals and are closely related to their evolutionary status and level of adaptive capabilities. The range of preferred temperatures for reptiles (28°C - 32°C) coincides with the zone of temperature-dependent increase in the rate of the M-cholinergic reaction in the brain, which was previously found in warm-blooded neurons. The growth of the M-cholinergic process contributes to the transition of adaptive behavior to a higher level. Of the cold-blooded, only reptiles actively use thermoregulatory behavior as a tool to achieve a temperature optimum. This paper is devoted to the study of the behavior of red-eared turtles aimed at reaching the range of preferred temperatures. Temperature conditions necessary for the survival of different groups of cold-blooded animals are compared and the reason for temperature preferences is discussed. Methods: The behavior of turtles was studied under conditions of variable solar radiation and in a 3-section terrarium with gradual temperature ranges: 23°C - 24°C;28°C - 31°C and 45°C - 50°C. Results: It was found that prolonged (up to 1.5 hours) heating at a temperature of 45°C - 50°C was the best way to achieve the preferred temperatures. This method of heating results in increasing the temperature of the shell to an average of 37°C, followed by a very slow decrease during 4 - 6 hours within the limits that closely coincided with the preferred level. Conclusion: The results obtained demonstrate that the main function of the turtle shell is to accumulate heat and keep it for a long time in a variable climate. The preferred temperature achieved in this case is necessary for the temperature-dependent transition of the rate of the M-cholinergic reaction in the brain to a higher level, which creates more significant adaptive capabilities. The temperature range of the M-cholinergic process has two inflection points at 27°C - 29°C and 34°C - 36°C. In accordance with these values, the temperature preferences of cold-blooded animals are divided into three groups: 0°C - 28°C (fish and amphibians);28°C - 32°C (reptiles) and 34°C - 36°C (dinosaurs). Different ranges of preferred temperatures correspond to three stages of adaptive development.
文摘The main purpose of this study is to investigate temperature preference for habitat of three species of oceanic sea skaters, Halobates micans, H. germanus and H. sericeus. For each of the three species, we examined the relationship between population density and surface water and air temperatures in the sampling sites during three science cruises in the tropical to temperate zone of the Pacific Ocean. A higher density of H. micans was observed in sites with higher water and air temperatures at 28℃?- 30℃?than that at site with lower temperatures of 23℃?- 28℃. A higher density of H. germanus was observed in sites with extremely high temperatures of 29.6℃?and 30℃?than that in sites with moderately high temperatures of 28℃?- 29℃?in the Pacific Ocean, while a relatively high density was observed in sites with a wide range of temperatures from 24℃?- 30℃?in the southern hemisphere Pacific Ocean. The relatively low temperature preference of 23℃?- 28℃?exhibited by H. sericeus may be related to its size as the smallest among the three species and its relatively wide latitudinal distribution ranging up to 40?N.
文摘The big-headed turtle Platysternon megacephalum is a stream-dwelling species whose ecology is poorly known. We carried out field and laboratory investigations to determine field body temperatures and thermal preference of this species. In the field, the body temperatures of the turtles conformed to the water temperature, with little diel variation in either summer or au- tumn. Over the diel cycle, the mean body temperatures ranged from 20.8℃ to 22.2℃ in summer and from 19.3℃ to 21.2℃ in autumn; the highest body temperatures ranged from 22.1℃ to 25.0℃ in summer and from 20.6℃ to 23.8℃ in autumn. In the laboratory, the preferred body temperature （Tp） was 25.3℃ Food intake was maximized at 24.0℃, whereas locomotor perfor- mance peaked at 30.0℃. Consequently, Tp was closer to the thermal optimum for food intake than for locomotion. Therefore, this freshwater turtle has relative low field body temperatures corresponding to its thermal environment. In addition, the turtle prefers low temperatures and has a low optimal temperature for food intake [Current Zoology 59 （5）： 626-632, 20＇13].
