scholarly journals Behavioral and Thermoregulatory Responses to Changes in Ambient Temperature and Wheel Running Availability in Octodon degus

2021 ◽  
Vol 15 ◽  
Author(s):  
Beatriz Bano-Otalora ◽  
Maria Angeles Rol ◽  
Juan Antonio Madrid

Octodon degus is primarily a diurnal species, however, in laboratory conditions, it can switch from diurnal to nocturnal in response to wheel running availability. It has been proposed that this activity inversion obeys thermoregulatory constraints induced by vigorous physical exercise. Thus, its activity shifts to the night as the ambient temperature is lower.Here, we investigate the relationship between thermoregulation and the activity phase-inversion in response to wheel-running in this species. We measured behavioral activity and body temperature rhythms in diurnal naïve animals under 12 h light: 12 h dark cycles at four different ambient temperatures (spanning from ~26°C to 32°C), and following access to running wheels while maintained under high ambient temperature.Our results show that naïve degus do not shift their diurnal activity and body temperature rhythms to a nocturnal phase when subjected to sequential increases in ambient temperature. However, when they were provided with wheels under constant high-temperature conditions, all animals inverted their diurnal phase preference becoming nocturnal. Both, negative masking by light and entrainment to the dark phase appeared involved in the nocturnalism of these animals. Analysis of the thermoregulatory response to wheel running revealed some differences between masked and entrained nocturnal chronotypes.These data highlight the importance of the coupling between wheel running availability and ambient temperature in the nocturnalism of the degus. The results support the view that an innate “protective” pre-program mechanism (associating darkness and lower ambient temperature) may change the timing of behavioral activity in this species to reduce the potential risk of hyperthermia.

1975 ◽  
Vol 53 (6) ◽  
pp. 679-685 ◽  
Author(s):  
J. B. Holter ◽  
W. E. Urban Jr. ◽  
H. H. Hayes ◽  
H. Silver ◽  
H. R. Skutt

Six adult white-tailed deer (Odocoileus virginianus borealis) were exposed to 165 periods of 12 consecutive hours of controlled constant ambient temperature in an indirect respiration calorimeter. Temperatures among periods varied from 38 to 0 (summer) or to −20C (fall, winter, spring). Traits measured were energy expenditure (metabolic rate), proportion of time spent standing, heart rate, and body temperature, the latter two using telemetry. The deer used body posture extensively as a means of maintaining body energy equilibrium. Energy expenditure was increased at low ambient temperature to combat cold and to maintain relatively constant body temperature. Changes in heart rate paralleled changes in energy expenditure. In a limited number of comparisons, slight wind chill was combatted through behavioral means with no effect on energy expenditure. The reaction of deer to varying ambient temperatures was not the same in all seasons of the year.


1962 ◽  
Vol 15 (2) ◽  
pp. 386 ◽  
Author(s):  
PR Morrison

Body temperature measurements on the short-nosed bandicoot (Thylacis obeaulus) have shown a nocturnal cycle with a range of 1� 2�C and a short active phase at 2200-0400 hr. The bilby or rabbit bandicoot (Macrotis lagoti8) had a sharply defined temperature cycle, with a range of almost 3�C after several months of captivity, during which the day-time resting temperature was progressively lowered from 36� 4 to 34� 2�C. Forced activity raised the diurnal temperature substantially but not to the nocturnal level. Forced activity did not raise the nocturnal level which was similar in the two species (37' O�C). Both species could regulate effectively at an ambient temperature of 5�C, but only Thylaci8 showed regulation at ambient temperatures of between 30 and 40�C.


2018 ◽  
Vol 35 ◽  
pp. 1-9 ◽  
Author(s):  
Nathalia Rocha Matias ◽  
Laura Verrastro

Studies on the thermal biology of fossorial reptiles that examine the relationship between the body temperature and thermal environment are needed to determine the extent of their thermoregulation abilities. This study assessed the thermal biology of Amphisbaena munoai Klappenbach, 1969 in the rocky fields of the Rio Grande do Sul and in the laboratory. The body temperature of most individuals was between 24 and 30 °C, both in the field (n = 81) and laboratory (n = 19). More individuals were caught in winter (n = 55) and spring (n = 60) than in summer (n = 25) and fall (n = 45), and in spring, individuals showed similar nocturnal and diurnal activities. In the laboratory, we found individuals with body temperatures up to 5 °C higher than the ambient temperature (n = 4), suggesting that some physiological mechanisms participate in the thermoregulation of these animals. Amphisbaena munoai is a thigmothermic species that is capable of actively regulating its temperature by selecting microhabitats such that its various activities occur within an ideal temperature range. This study is the first to evaluate the effect of seasonality and diurnal and nocturnal variations on the thermoregulation of an amphisbaenid.


1965 ◽  
Vol 20 (3) ◽  
pp. 405-410 ◽  
Author(s):  
Hermann Pohl

Characteristics of cold acclimation in the golden hamster, Mesocricetus auratus, were 1) higher metabolic rate at -30 C, 2) less shivering when related to ambient temperature or oxygen consumption, and 3) higher differences in body temperature between cardiac area and thoracic subcutaneous tissues at all ambient temperatures tested, indicating changes in tissue insulation. Cold-acclimated hamsters also showed a rise in temperature of the cardiac area when ambient temperature was below 15 C. Changes in heat distribution in cold-acclimated hamsters suggest higher blood flow and heat production in the thoracic part of the body in the cold. The thermal conductance through the thoracic and lumbar muscle areas, however, did not change notably with lowering ambient temperature. Marked differences in thermoregulatory response to cold after cold acclimation were found between two species, the golden hamster and the thirteen-lined ground squirrel, showing greater ability to regulate body temperature in the cold in hamsters. hibernator; oxygen consumption— heat production; body temperature — heat conductance; muscular activity — shivering; thermoregulation Submitted on July 6, 1964


Endocrinology ◽  
2014 ◽  
Vol 155 (7) ◽  
pp. 2613-2623 ◽  
Author(s):  
S.E. Royston ◽  
N. Yasui ◽  
A.G. Kondilis ◽  
S.V. Lord ◽  
J.A. Katzenellenbogen ◽  
...  

Estrogenic signaling shapes and modifies daily and circadian rhythms, the disruption of which has been implicated in psychiatric, neurologic, cardiovascular, and metabolic disease, among others. However, the activational mechanisms contributing to these effects remain poorly characterized. To determine the activational impact of estrogen on daily behavior patterns and differentiate between the contributions of the estrogen receptors ESR1 and ESR2, ovariectomized adult female mice were administered estradiol, the ESR1 agonist propylpyrazole triol, the ESR2 agonist diarylpropionitrile, or cholesterol (control). Animals were singly housed with running wheels in a 12-hour light, 12-hour dark cycle or total darkness. Estradiol increased total activity and amplitude, consolidated activity to the dark phase, delayed the time of peak activity (acrophase of wheel running), advanced the time of activity onset, and shortened the free running period (τ), but did not alter the duration of activity (α). Importantly, activation of ESR1 or ESR2 differentially impacted daily and circadian rhythms. ESR1 stimulation increased total wheel running and amplitude and reduced the proportion of activity in the light vs the dark. Conversely, ESR2 activation modified the distribution of activity across the day, delayed acrophase of wheel running, and advanced the time of activity onset. Interestingly, τ was shortened by estradiol or either estrogen receptor agonist. Finally, estradiol-treated animals administered a light pulse in the early subjective night, but no other time, had an attenuated response compared with controls. This decreased phase response was mirrored by animals treated with diarylpropionitrile, but not propylpyrazole triol. To conclude, estradiol has strong activational effects on the temporal patterning and expression of daily and circadian behavior, and these effects are due to distinct mechanisms elicited by ESR1 and ESR2 activation.


2017 ◽  
Vol 39 (1) ◽  
pp. 48 ◽  
Author(s):  
K. A. Descovich ◽  
S. Johnston ◽  
A. Lisle ◽  
V. Nicolson ◽  
T. Janssen ◽  
...  

The southern hairy-nosed wombat (Lasiorhinus latifrons) is a nocturnal, fossorial marsupial that has evolved a range of physiological and behavioural adaptations to its semiarid environment. This study describes long-term core body temperature (Tb) of L. latifrons in a population with opportunities for behavioural thermoregulation through burrow use. Tb was measured hourly in 12 captive L. latifrons using implanted dataloggers over a 9-month period from late winter to late autumn. Data were examined for daily patterns, seasonal changes, sex differences and the relationship with environmental conditions (ambient temperature, den temperature and relative humidity). Tb ranged from 30.9 to 38.8°C, and had a distinct nychthemeral rhythm, with peak temperatures occurring at night in line with nocturnal activity. Females had a higher mean Tb (34.9°C) than males (34.4°C). The relationship between external ambient temperature and body temperature was negative, with body temperature decreasing as ambient temperature increased. This study is an important step towards a comprehensive picture of thermoregulation in L. latifrons, which may become vulnerable in the future if environmental temperatures rise and water availability decreases.


2008 ◽  
Vol 294 (3) ◽  
pp. R956-R965 ◽  
Author(s):  
Kevin J. Cummings ◽  
Chris Willie ◽  
Richard J. A. Wilson

Mild reductions in ambient temperature dramatically increase the mortality of neonatal mice deficient in pituitary adenylate cyclase-activating polypeptide (PACAP), with the majority of animals succumbing in the second postnatal week. During anesthesia-induced hypothermia, PACAP−/− mice at this age are also vulnerable to prolonged apneas and sudden death. From these observations, we hypothesized that before the onset of genotype-specific mortality and in the absence of anesthetic, the breathing of PACAP-deficient mice is more susceptible to mild reductions in ambient temperature than wild-type littermates. To test this hypothesis, we recorded breathing in one group of postnatal day 4 PACAP+/+, +/−, and −/− neonates (using unrestrained, flow-through plethysmography) and metabolic rate in a separate group (using indirect calorimetry), both of which were exposed acutely to ambient temperatures slightly below (29°C), slightly above (36°C), or at thermoneutrality (32°C). At 32°C, the breathing frequency of PACAP−/− neonates was significantly less than PACAP+/+ littermates. Reducing the ambient temperature to 29°C caused a significant suppression of tidal volume and ventilation in both PACAP+/− and −/− animals, while the tidal volume and ventilation of PACAP+/+ animals remained unchanged. Genotype had no effect on the ventilatory responses to ambient warming. At all three ambient temperatures, genotype had no influence on oxygen consumption or body temperature. These results suggest that during mild reductions in ambient temperature, PACAP is vital for the preservation of neonatal tidal volume and ventilation, but not for metabolic rate or body temperature.


1989 ◽  
Vol 143 (1) ◽  
pp. 211-223 ◽  
Author(s):  
G. N. STONE ◽  
P. G. WILLMER

‘Grab and stab’ methods have become standard in the measurement of insect body temperatures. The gradient of the best-fit regression of body temperature on ambient temperature is often used as a measure of the thermoregulatory ability of a species. The temperatures recorded are commonly accepted as slight underestimates of actual values prior to capture due to passive cooling between capture and insertion of the thermocouple. Here we present laboratory experiments involving tethered flight which show that bees often warm up on cessation of flight, and that errors due to warm-up over the time interval typically associated with ‘grab and stab’ sampling may be significant. More importantly, the errors due to warm-up in two species are shown to change with ambient temperature, thus affecting the form of the relationship between ambient and body temperatures. We compare laboratory and field data to illustrate the way in which warm-up errors may exaggerate apparent thermoregulatory ability, and we urge greater caution in the interpretation of ‘grab and stab’ data.


1994 ◽  
Vol 42 (1) ◽  
pp. 65 ◽  
Author(s):  
BG Lovegrove ◽  
G Heldmaier

The maximum amplitudes of circadian rhythms of body temperature (R(t)) of three species of desert rodents inhabiting an arboreal-subterranean gradient were correlated with habitat-dependent thermoregulatory parameters such as minimal thermal conductance and the magnitude of ambient temperature tolerance by endotherms. It was shown that R(t) differed by 87-181% of expected values. The data for two rodents (Thallomys paedulcus and Aethomys namaquensis) that forage aboveground displayed higher-than-expected R(t) values, whereas the strictly subterranean species (Cryptomys damarensis) had lower-than-expected R(t) values. These data are interpreted in terms of the Endothermic Temperature Range Hypothesis, which argues that the large range of diel ambient temperature fluctuations found in desert habitats may account for the physiological parameters that generate the higher-than-expected body temperature rhythms, a low and fairly inflexible minimal thermal conductance and low resting metabolic rate. Further discussion centres on the possible functional significance of circadian energetic rhythms, particularly in terms of an endotherm's fitness. It is proposed that, at least, functions of the rhythms should be considered: diel thermoregulatory adjustments and energy conservation.


1986 ◽  
Vol 34 (1) ◽  
pp. 25 ◽  
Author(s):  
JR Roberts ◽  
RV Baudinette

Stubble quail occur in more arid areas of Australia than king quail; however, the rates of metabolism and the ability to regulate body temperature in response to varying ambient temperature are similar in both birds, and resemble those of other quail species. At high ambient temperatures, rates of heat loss mediated by evaporative water loss are lower than those previously reported for more xerophilic species. Overall rates of water turnover and evaporative water loss at lower ambient temperatures are at the lower end of the range predicted for birds.


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