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• 1. [Article] The metabolic cost of behavioral thermoregulation of body temperature in the northern alligator lizard Gerrhonotus coeruleus, and how it affects the classical concept of eurythermality

  The effect of total metabolic cost expenditures on the precision of behavioral thermoregulation was investigated for the purportedly eurythermic Northern Alligator lizard (Gerrhonotus coeruleus). An operant ...

  Citation × Citation Citation Abstract Copy Title: The metabolic cost of behavioral thermoregulation of body temperature in the northern alligator lizard Gerrhonotus coeruleus, and how it affects the classical concept of eurythermality Author: Campbell, James Dudley Year: 1981 The effect of total metabolic cost expenditures on the precision of behavioral thermoregulation was investigated for the purportedly eurythermic Northern Alligator lizard (Gerrhonotus coeruleus). An operant apparatus was designed to test metabolic output at different heat reinforcement magnitudes. The mean TB reflected in each trial was positively correlated to the length of reinforcement. The shuttle rate during each trial was inversely correlated to the length of reinforcement. The standard deviation and total metabolic costs did not vary significantly between trials undertaken at the same ambient temperature. Eurythermality in G. coeruleus is caused by fluctuations in preferred body temperature and not by fluctuations around this temperature. The metabolic cost of behavioral thermoregulation did not change with corresponding changes in reinforcement magnitude. This indicates that eurythermality is the recorded effect of lizards behaviorally regulating to different TB in a stenothermic manner, rather than of random TB fluctuations in a wide range of normal activity (the classical view of eurythermality). Title: The metabolic cost of behavioral thermoregulation of body temperature in the northern alligator lizard Gerrhonotus coeruleus, and how it affects the classical concept of eurythermality Author: Campbell, James Dudley Year: 1981 The effect of total metabolic cost expenditures on the precision of behavioral thermoregulation was investigated for the purportedly eurythermic Northern Alligator lizard (Gerrhonotus coeruleus). An operant apparatus was designed to test metabolic output at different heat reinforcement magnitudes. The mean TB reflected in each trial was positively correlated to the length of reinforcement. The shuttle rate during each trial was inversely correlated to the length of reinforcement. The standard deviation and total metabolic costs did not vary significantly between trials undertaken at the same ambient temperature. Eurythermality in G. coeruleus is caused by fluctuations in preferred body temperature and not by fluctuations around this temperature. The metabolic cost of behavioral thermoregulation did not change with corresponding changes in reinforcement magnitude. This indicates that eurythermality is the recorded effect of lizards behaviorally regulating to different TB in a stenothermic manner, rather than of random TB fluctuations in a wide range of normal activity (the classical view of eurythermality). Close

• 2. [Article] Effects of intraperitoneal and intracerebral injections of Triiodothyronine on temperature selection in fish

  Goldfish (Carassius auratus) of 15-28g were maintained at 23 C and subsequently were intraperitoneally injected with saline (controls) and varying doses of Triiodothyronine (T3). Following the injection, ...

  Citation × Citation Citation Abstract Copy Title: Effects of intraperitoneal and intracerebral injections of Triiodothyronine on temperature selection in fish Author: Grahn, Dennis A. Year: 1984 Goldfish (Carassius auratus) of 15-28g were maintained at 23 C and subsequently were intraperitoneally injected with saline (controls) and varying doses of Triiodothyronine (T3). Following the injection, the fish were placed in a thermal gradient and temperature selection and activity monitored for 30 min. There was no- significant difference between the responses of the experimental fish to the 2 different doses of T3. However, there was a significant difference in response between the experimental and control groups (P < 0.001). The decreased temperature selection occurred early in the test runs, while the increased activity began later. Larger goldfish (175-205g) received 0.5 μl intracerebral injections of 1.5-3.0 ng T3 in the anterior brainstem via an indwelling cannula injection system. These fish responded to the injections by selecting cooler water. The magnitude of the response was related to the distance of the injection site from the preoptic/anterior hypothalamic region. I conclude that increased plasma levels of T3 lead to the selection of cooler water. This effect appeared to be mediated via the anterior brainstem. Injected T3 also produced hyperactivity. This latter effect developed more slowly and appeared to be more diffusely mediated. Title: Effects of intraperitoneal and intracerebral injections of Triiodothyronine on temperature selection in fish Author: Grahn, Dennis A. Year: 1984 Goldfish (Carassius auratus) of 15-28g were maintained at 23 C and subsequently were intraperitoneally injected with saline (controls) and varying doses of Triiodothyronine (T3). Following the injection, the fish were placed in a thermal gradient and temperature selection and activity monitored for 30 min. There was no- significant difference between the responses of the experimental fish to the 2 different doses of T3. However, there was a significant difference in response between the experimental and control groups (P < 0.001). The decreased temperature selection occurred early in the test runs, while the increased activity began later. Larger goldfish (175-205g) received 0.5 μl intracerebral injections of 1.5-3.0 ng T3 in the anterior brainstem via an indwelling cannula injection system. These fish responded to the injections by selecting cooler water. The magnitude of the response was related to the distance of the injection site from the preoptic/anterior hypothalamic region. I conclude that increased plasma levels of T3 lead to the selection of cooler water. This effect appeared to be mediated via the anterior brainstem. Injected T3 also produced hyperactivity. This latter effect developed more slowly and appeared to be more diffusely mediated. Close

• 3. [Article] The effect of developmental temperature on morphology, energy metabolism, growth hormone and thyroid stimulating hormone in Long-Evans rats

  Long-Evans rats were raised from birth to eight weeks of age at 5°C, 20°C and 30°C. Blood was taken from animals two to eight weeks of age and assayed for growth hormone and thyroid stimulating hormone. ...

  Citation × Citation Citation Abstract Copy Title: The effect of developmental temperature on morphology, energy metabolism, growth hormone and thyroid stimulating hormone in Long-Evans rats Author: Quinn, Dana Elizabeth Year: 1978 Long-Evans rats were raised from birth to eight weeks of age at 5°C, 20°C and 30°C. Blood was taken from animals two to eight weeks of age and assayed for growth hormone and thyroid stimulating hormone. The 30°C reared rats were found to have the longest ear, tail and hind limbs, followed by the 20°C reared rats. The 5°C rats were found to have the shortest ear, tail and hind limb. The 30°C and 5°C reared rats were found to have similar masses at the termination of the experiment. The 20°C reared rats had the smallest mass. Differences in size between the three groups when compared on a weekly basis were not found to be related to weekly obtained serum levels of growth hormone and thyroid stimulating hormone. Food consumption was greatest for the 5°C reared rats followed by the 20°C reared rats. The 5°C reared rats were found to have the lowest routine metabolic rate in the 5°C chamber. The 20°C reared rats were found to have the lowest routine metabolic rate in both the 20°c and 30°C chamber. When 30°C and 20°C reared rats were put in the 5°C chamber with the 5°C reared rats, they initially lost mass, however after three weeks in the 5°C chamber they began to gain mass. The 30°C reared rats gained mass at a greater rate than did the 20°C reared rats. The 5°C reared rats continued to gain mass throughout this period. While in the 5°C chamber the total food consumption of the 20°c reared rats was the greatest, whereas the 5°C and 30°C reared rats consumed similar amounts of food. Title: The effect of developmental temperature on morphology, energy metabolism, growth hormone and thyroid stimulating hormone in Long-Evans rats Author: Quinn, Dana Elizabeth Year: 1978 Long-Evans rats were raised from birth to eight weeks of age at 5°C, 20°C and 30°C. Blood was taken from animals two to eight weeks of age and assayed for growth hormone and thyroid stimulating hormone. The 30°C reared rats were found to have the longest ear, tail and hind limbs, followed by the 20°C reared rats. The 5°C rats were found to have the shortest ear, tail and hind limb. The 30°C and 5°C reared rats were found to have similar masses at the termination of the experiment. The 20°C reared rats had the smallest mass. Differences in size between the three groups when compared on a weekly basis were not found to be related to weekly obtained serum levels of growth hormone and thyroid stimulating hormone. Food consumption was greatest for the 5°C reared rats followed by the 20°C reared rats. The 5°C reared rats were found to have the lowest routine metabolic rate in the 5°C chamber. The 20°C reared rats were found to have the lowest routine metabolic rate in both the 20°c and 30°C chamber. When 30°C and 20°C reared rats were put in the 5°C chamber with the 5°C reared rats, they initially lost mass, however after three weeks in the 5°C chamber they began to gain mass. The 30°C reared rats gained mass at a greater rate than did the 20°C reared rats. The 5°C reared rats continued to gain mass throughout this period. While in the 5°C chamber the total food consumption of the 20°c reared rats was the greatest, whereas the 5°C and 30°C reared rats consumed similar amounts of food. Close

• 4. [Article] Biogeography of the American Pika (Ochotona princeps) in Oregon and Southern Washington : illuminating genetic relationships among disjunct populations

  The American pika (Ochotona princeps) finds moderately warm temperatures (>25°C) lethally stressful, and at the end of the last Ice Age 10,000 years ago was forced to disperse to cooler, "sky island" mountaintops ...

  Citation × Citation Citation Abstract Copy Title: Biogeography of the American Pika (Ochotona princeps) in Oregon and Southern Washington : illuminating genetic relationships among disjunct populations Author: Batten, George Washington, III Year: 2010 The American pika (Ochotona princeps) finds moderately warm temperatures (>25°C) lethally stressful, and at the end of the last Ice Age 10,000 years ago was forced to disperse to cooler, "sky island" mountaintops where they are almost exclusively found today. Thirty six subspecies are recognized, all established using morphological characters, and it is uncertain whether these subspecies' designations are corroborated by genetic analyses. This study elucidates three hypotheses regarding populations in Oregon and southern Washington: 1) O. p. fumosa constitutes a subspecies distinct form O. p. brunnescens, 2) the Columbia River constitutes a barrier to gene flow giving rise to two subspecies rather than the single subspecies O. p. brunnescens, and 3) populations in eastern Oregon ( O. p. jewetti and O. p. taylori) are genetically distinct from populations in the Cascade Range ( 0. p. brunnescens and O. p. fumosa). Title: Biogeography of the American Pika (Ochotona princeps) in Oregon and Southern Washington : illuminating genetic relationships among disjunct populations Author: Batten, George Washington, III Year: 2010 The American pika (Ochotona princeps) finds moderately warm temperatures (>25°C) lethally stressful, and at the end of the last Ice Age 10,000 years ago was forced to disperse to cooler, "sky island" mountaintops where they are almost exclusively found today. Thirty six subspecies are recognized, all established using morphological characters, and it is uncertain whether these subspecies' designations are corroborated by genetic analyses. This study elucidates three hypotheses regarding populations in Oregon and southern Washington: 1) O. p. fumosa constitutes a subspecies distinct form O. p. brunnescens, 2) the Columbia River constitutes a barrier to gene flow giving rise to two subspecies rather than the single subspecies O. p. brunnescens, and 3) populations in eastern Oregon ( O. p. jewetti and O. p. taylori) are genetically distinct from populations in the Cascade Range ( 0. p. brunnescens and O. p. fumosa). Close