Effects of polychlorinated biphenyls on the metabolic rates of mourning doves exposed to low ambient temperatures

1981 ◽  
Vol 27-27 (1) ◽  
pp. 678-682 ◽  
Author(s):  
Gildo M. Tori ◽  
Larry P. Mayer
1999 ◽  
Vol 202 (21) ◽  
pp. 3021-3028 ◽  
Author(s):  
T.C. Hoffman ◽  
G.E. Walsberg

We tested the hypothesis that birds can rapidly change the conductance of water vapor at the skin surface in response to a changing need for evaporative heat loss. Mourning doves (Zenaida macroura) were placed in a two-compartment chamber separating the head from the rest of the body. The rate of cutaneous evaporation was measured in response to dry ventilatory inflow at three ambient temperatures and in response to vapor-saturated ventilatory inflow at two ambient temperatures. At 35 degrees C, cutaneous evaporation increased by 72 % when evaporative water loss from the mouth was prevented, but no increase was observed at 45 degrees C. For both dry and vapor-saturated treatments, cutaneous evaporation increased significantly with increased ambient temperature. Changes in skin temperature made only a minor contribution to any observed increase in cutaneous evaporation. This indicates that Z. macroura can effect rapid adjustment of evaporative conductance at the skin in response to acute change in thermoregulatory demand.


2015 ◽  
Vol 282 (1804) ◽  
pp. 20142781 ◽  
Author(s):  
Eran Levin ◽  
Brit Plotnik ◽  
Eran Amichai ◽  
Luzie J. Braulke ◽  
Shmulik Landau ◽  
...  

We report that two species of mouse-tailed bats ( Rhinopoma microphyllum and R. cystops ) hibernate for five months during winter in geothermally heated caves with stable high temperature (20°C). While hibernating, these bats do not feed or drink, even on warm nights when other bat species are active. We used thermo-sensitive transmitters to measure the bats’ skin temperature in the natural hibernacula and open flow respirometry to measure torpid metabolic rate at different ambient temperatures ( T a , 16–35°C) and evaporative water loss (EWL) in the laboratory. Bats average skin temperature at the natural hibernacula was 21.7 ± 0.8°C, and no arousals were recorded. Both species reached the lowest metabolic rates around natural hibernacula temperatures (20°C, average of 0.14 ± 0.01 and 0.16 ± 0.04 ml O 2 g −1 h −1 for R. microphyllum and R. cystops , respectively) and aroused from torpor when T a fell below 16°C. During torpor the bats performed long apnoeas (14 ± 1.6 and 16 ± 1.5 min, respectively) and had a very low EWL. We hypothesize that the particular diet of these bats is an adaptation to hibernation at high temperatures and that caves featuring high temperature and humidity during winter enable these species to survive this season on the northern edge of their world distribution.


2006 ◽  
Vol 274 (1607) ◽  
pp. 287-293 ◽  
Author(s):  
Craig R White ◽  
Tim M Blackburn ◽  
Graham R Martin ◽  
Patrick J Butler

A classic example of ecophysiological adaptation is the observation that animals from hot arid environments have lower basal metabolic rates (BMRs, ml O 2  min −1 ) than those from non-arid (luxuriant) ones. However, the term ‘arid’ conceals within it a multitude of characteristics including extreme ambient temperatures ( T a , °C) and low annual net primary productivities (NPPs, g C m −2 ), both of which have been shown to correlate with BMR. To assess the relationship between environmental characteristics and metabolic rate in birds, we collated BMR measurements for 92 populations representing 90 wild-caught species and examined the relationships between BMR and NPP, T a , annual temperature range ( T r ), precipitation and intra-annual coefficient of variation of precipitation ( P CV ). Using conventional non-phylogenetic and phylogenetic generalized least-squares approaches, we found no support for a relationship between BMR and NPP, despite including species captured throughout the world in environments spanning a 35-fold range in NPP. Instead, BMR was negatively associated with T a and T r , and positively associated with P CV .


1986 ◽  
Vol 64 (2) ◽  
pp. 322-327 ◽  
Author(s):  
Lyle A. Renecker ◽  
Robert J. Hudson

Metabolic rates and thermoregulatory responses were studied in adult moose (Alces alces) exposed to various ambient temperatures during winter and summer. Resting energy expenditures followed a marked annual cycle with a maximum (940 kJ kg body weight−0.75 d−1) during spring – early summer and minimum (430 kJ kg body weight−0.75 d−1) during winter. The heat increment of feeding associated with a pelleted ration was 6–9 kJ kg body weight−0.75 h−1. The energy cost of standing was 4.2 kJ kg body weight−0.75 h−1, an increment of 25% over the lying posture. Although piloerection was observed between −25 and −30 °C, metabolic rates did not increase. In contrast to their cold tolerance, moose were easily heat stressed. During winter, moose increased respiration rates when ambient temperatures rose above −5 °C. Resistance to heat load was greater for standing moose during summer; respiration rate increased above 14 °C and open-mouthed panting began at 20 °C. Energy expenditure and heart rate followed a similar rise with increasing ambient temperature.


1971 ◽  
Vol 13 (2) ◽  
pp. 303-313 ◽  
Author(s):  
D. B. Stephens

SUMMARY1. The metabolic rates of 58 individual piglets kept either on a straw or on a concrete floor at ambient temperatures near to 10°, 20° or 30°C have been measured with ages ranging from newborn to 9 days, and body weight from 1·0 to 3·2 kg. The oxygen consumption was measured on each floor material at the chosen ambient temperature thus allowing paired comparisons for each animal.2. In comparison with the concrete floor, oxygen consumption on straw was reduced by 18% at 10°C, 27% at 20°C and by 12% at 30°C for pigs 2 to 9 days old. The regression coefficients of mean log (oxygen consumption) on log (body weight) were around 0·66 at 10° and 20°C. At 30°C the value was 0·99 ± 0·14. The regression coefficients were not significantly affected by the presence of a straw floor showing that its effect did not vary with body weight. Corresponding values foi piglets below 24 hours of age were 17% at 10°C, 27% at 20°C and 22% at 30°C ambient temperature.3. Moving a piglet on to a straw floor at 10°C had the same thermal effect as raising the ambient temperature to 18°C. Similar treatment at 30°C was equivalent to raising the ambient temperature to 32°C.4. Lowering ambient temperature to increase the temperature gradient between the homeothermic body of the piglet and the environment progressively increased heat loss in all cases. There was a concomitant decrease in the calculated conductance between core and environment which was more pronounced for the piglets lying on the concrete floor.


1979 ◽  
Vol 59 (3) ◽  
pp. 611-617 ◽  
Author(s):  
R. J. CHRISTOPHERSON ◽  
R. J. HUDSON ◽  
M. K. CHRISTOPHERSEN

The metabolic rates of two bison and four Hereford spring-born calves were measured at monthly intervals from December until the following November. Following adaptation at seasonal ambient temperatures, metabolic measurements were made while calves were exposed to controlled temperatures of +10, 0 and −30 °C. Exposure of the Hereford calves to −30 °C resulted in increased metabolic rates during the first 6 mo of the study but the magnitude of the response was greatly attenuated as the calves grew larger. At −30 °C, bison calves either maintained or reduced metabolic rates compared to expenditures at +10 °C. When the calves were about 17 mo of age, they were exposed to a combination of low temperatures and wind. Wind velocities of 4.7 km∙h−1 did not influence metabolic rates of either bison or Herefords at air temperatures of 0 °C. However, at −30 °C, metabolic rates increased from 650 and 700 KJ∙kg−.75∙d−1 to 835 and 950 KJ∙kg−.75∙d−1 in Hereford and bison calves, respectively. Neither respiratory frequencies nor heart rates were influenced significantly during cold exposure, but heart rates increased in response to wind. In general, metabolic rates and heart rates were lower in bison calves.


1972 ◽  
Vol 50 (10) ◽  
pp. 1243-1250 ◽  
Author(s):  
G. Untergasser ◽  
J. S. Hayward

The embryos of mallards and scaups show no evidence of homeothermy before the point of hatching. The ability to thermoregulate develops quickly directly after hatching, so that day-old mallards remain homeothermic for at least 2.5 h at ambient temperatures down to +2 °C. The lowest ambient temperatures at which 1-day-old scaups and common eiders remain homeothermic for at least 2.5 h are −2 °C and −7 °C respectively. This rapid development of cold resistance is related to increases in peak metabolic rates and insulative capacities. In embryos of pipped eggs, metabolic rates do not exceed 1.1 ml O2/g h for mallards and 1.6 ml/g h for scaups, while the peak metabolic rates of the day-old young are 6.1 and 7.0 ml/g h respectively. One-day-old common eiders have a peak metabolic rate of about 5 ml/g h. After an age of 3 days, cold resistance increases with age while peak metabolic rates decrease, indicating that reduced heat loss contributes to increased cold resistance. At an age of 7 days, mallards can maintain homeothermy for at least 2.5 h at −4 °C, scaups at −14 °C, and common eiders at −16 °C. Insulation indices of eider ducklings are significantly higher than those of young mallards and scaups.


1986 ◽  
Vol 250 (3) ◽  
pp. R377-R382 ◽  
Author(s):  
M. E. Heath ◽  
H. T. Hammel

Body temperatures and rates of O2 consumption and CO2 production were measured in four Chinese pangolins (Manis pentadactyla) during short-term exposures (2-4 h) to ambient temperatures (Ta) of 10-34 degrees C. At Ta less than 27 degrees C the pangolins curled into a sphere. At Ta greater than 28 degrees C the animals laid on their backs with their soft abdominal skin exposed. Rectal temperatures between 33.4 and 35.5 degrees C were recorded from animals exposed to Ta of 10-32 degrees C. At Ta greater than or equal to 32 degrees C the animals appeared to be markedly heat stressed, rate of breathing was elevated, and core temperature rose somewhat. Resting metabolic rates averaged 3.06 ml O2 X kg-1 X min-1. This is significantly lower than would be predicted from the relationship between body mass and metabolic rate established by Kleiber (The Fire of Life: an Introduction to Animal Energetics. New York: Wiley, 1975) for other eutherian mammals. The magnitude of the metabolic response to Ta below the lower critical temperature was inversely correlated to the mass of the pangolin, the slope being greatest for the smallest animals. Respiratory quotients of 0.85-1.0 were observed.


1994 ◽  
Vol 191 (1) ◽  
pp. 59-88 ◽  
Author(s):  
J Olson

The ontogeny of shivering thermogenesis was investigated in the altricial red-winged blackbird (Agelaius phoeniceus). Two indices of heat production ­ the rate of oxygen consumption (V(dot)O2) of the bird and the electromyographic (EMG) activity of the pectoralis (PECT) and gastrocnemius (GAST) muscles ­ were measured simultaneously in adult and nestling red-winged blackbirds as they were subjected first to thermoneutral temperatures and subsequently to progressively colder ambient temperatures (Ta). The ontogenetic changes in both indices indicated that the capability for thermogenesis in nestling red-winged blackbirds improved markedly with age. The metabolic rates of 3-day-old nestlings decreased during exposure to gradually falling ambient temperatures; at best, these nestlings were only able to maintain mass-specific V(dot)O2 at levels similar to or slightly above the resting metabolic rate at thermoneutral temperatures (RMR) for a short time before metabolic rates decreased with further cooling. Shivering was detected only in the PECT muscles and was of a relatively low intensity (maximum of sevenfold increase in intensity over basal levels). The 5-day-old nestlings increased mass-specific V(dot)O2 modestly (approximately 1.4-fold) above RMR and attained slightly higher maximal factorial increases in the EMG activity of the PECT (maximum of 18-fold basal levels) when exposed to the same experimental conditions. Shivering was also detected in the GAST muscles of these birds. The most striking improvements in both measures observed during the nestling period occurred between day 5 and day 8. Eight-day-old nestlings increased metabolic rates by approximately 2- to 2.5-fold over basal levels and sustained these elevated rates for longer before becoming hypothermic. Both the PECT and GAST muscles contributed significantly to shivering thermogenesis, and these older nestlings attained much higher factorial increases in the intensity of shivering (up to 72-fold) during exposure to cold temperatures. In addition, both the range and magnitude of the dominant frequencies of muscle activity in the PECT increased during postnatal development. The PECT muscles were a principal site of shivering thermogenesis in all nestling and adult red-winged blackbirds studied here. Shivering in these muscles was a 'first line defense' against cold; the threshold temperature for shivering in the PECT muscles coincided with the lower critical temperature for oxygen consumption (TLC), and the subsequent increases in EMG activity in this muscle with further cooling correlated well with the corresponding increases in mass-specific V(dot)O2.


1979 ◽  
Vol 57 (1) ◽  
pp. 149-155 ◽  
Author(s):  
Lawrence C. H. Wang

Using radiotelemetry for body-temperature sensing in field animals, torpor season in the Richardson's ground squirrel (Spermophilus richardsonii) was found to commence from mid-July in adults and mid-September in juveniles and to terminate for both groups in mid-March. The duration of torpor averaged 3 and 4.3 days in July and August and gradually lengthened to 19.1 days in January, after which it shortened to 14.2 and 6.0 days in February and March. The duration of intertorpor homeothermy ranged from 300 to 1500 min. The metabolic costs associated with entry into torpor, during torpor, arousal from torpor, and intertorpor were quantified in the laboratory at ambient temperatures comparable with those observed in burrow. Applying these metabolic data to the time budget for torpor in field animals, the estimated seasonal energetic costs for entry into torpor averaged 12.8% of total, deep torpor 16.6%, arousal from torpor 19.0%, and intertorpor 51.6%. The monthly energy savings by utilization of torpor ranged from 38.8% in July and 51.2% in March to between 81.6 and 96.0% between August and February. For the whole torpor season, which extended 8 months, the energy savings amounted to 87.8%.


Sign in / Sign up

Export Citation Format

Share Document