scholarly journals Do endotherms have thermal performance curves?

2021 ◽  
Vol 224 (3) ◽  
pp. jeb141309
Author(s):  
Danielle L. Levesque ◽  
Katie E. Marshall
Keyword(s):  
Body Temperature ◽  
Thermal Performance ◽  
Environmental Temperature ◽  
Comparative Approach ◽  
Evaporative Heat Loss ◽  
External Temperature ◽  
Performance Curves ◽  
Interspecific Comparisons ◽  
Measure Of Performance ◽  
Environmental Temperatures

ABSTRACTTemperature is an important environmental factor governing the ability of organisms to grow, survive and reproduce. Thermal performance curves (TPCs), with some caveats, are useful for charting the relationship between body temperature and some measure of performance in ectotherms, and provide a standardized set of characteristics for interspecific comparisons. Endotherms, however, have a more complicated relationship with environmental temperature, as endothermy leads to a decoupling of body temperature from external temperature through use of metabolic heat production, large changes in insulation and variable rates of evaporative heat loss. This has impeded our ability to model endothermic performance in relation to environmental temperature as well as to readily compare performance between species. In this Commentary, we compare the strengths and weaknesses of potential TPC analogues (including other useful proxies for linking performance to temperature) in endotherms and suggest several ways forward in the comparative ecophysiology of endotherms. Our goal is to provide a common language with which ecologists and physiologists can evaluate the effects of temperature on performance. Key directions for improving our understanding of endotherm thermoregulatory physiology include a comparative approach to the study of the level and precision of body temperature, measuring performance directly over a range of body temperatures and building comprehensive mechanistic models of endotherm responses to environmental temperatures. We believe the answer to the question posed in the title could be ‘yes’, but only if ‘performance’ is well defined and understood in relation to body temperature variation, and the costs and benefits of endothermy are specifically modelled.

Thermoregulation during the summer season in the Goode’s horned lizard Phrynosoma goodei (Iguania: Phrynosomatidae) in Sonoran Desert

2014 ◽  
Vol 35 (2) ◽  
pp. 161-172 ◽  
Author(s):  
Rafael Alejandro Lara-Resendiz ◽  
Tereza Jezkova ◽  
Philip C. Rosen ◽  
Fausto Roberto Méndez-de La Cruz
Keyword(s):  
Body Temperature ◽  
Sonoran Desert ◽  
Environmental Temperature ◽  
Biological Activities ◽  
Maximum Temperature ◽  
Temperature Range ◽  
Thermal Constraints ◽  
Preferred Body Temperature ◽  
Environmental Temperatures ◽  
Operative Temperatures

Reptiles in desert environments depend on habitat thermal quality to regulate their body temperature and perform biological activities. Understanding thermoregulation with respect to habitat thermal quality is critical for accurate predictions of species responses to climate change. We evaluated thermoregulation in Goode’s horned lizard, Phrynosoma goodei, and measured habitat thermal quality at the Reserva de la Biosfera El Pinacate y Gran Desierto de Altar, Sonora, Mexico, during the hottest season of the year. We found that field-active body temperature averaged 38.1 ± 0.38°C, preferred body temperature in laboratory averaged 34.9 ± 0.18°C and preferred body temperature range was 32.5-37.3°C. Operative temperature (i.e. environmental temperature available to the lizards) averaged 43.0 ± 0.07°C, with maximum temperature being near 70°C, and 62.9% of operative temperatures were above preferred body temperature range of P. goodei. Microhabitat thermal quality occupied by the lizards was high in the morning (7:00-10:30) and afternoon (5:50-dusk). We found that despite strong thermal constraints P. goodei was highly accurate and efficient in regulating its body temperature and that it presented a bimodal thermoregulatory pattern, being active in the mornings and in the evenings in order to avoid high mid-day environmental temperatures. Despite its thermoregulatory ability, P. goodei may be vulnerable to climate warming.

Shorn and unshorn Awassi sheep II. Pulse rate

1963 ◽  
Vol 60 (2) ◽  
pp. 169-173 ◽  
Author(s):  
E. Eyal
Keyword(s):  
Body Temperature ◽  
Pulse Rate ◽  
Environmental Temperature ◽  
Direct Sunlight ◽  
Ambient Temperatures ◽  
Awassi Sheep ◽  
Summer Temperatures ◽  
Vasomotor Activity ◽  
Environmental Temperatures ◽  
Daily Changes

1. A comparison was made between the pulse rate of shorn and unshorn sheep maintained in the shade and direct sunlight during the various seasons of the year.2. The variability of the pulse rate during the day generally agreed with the daily changes in body temperature and presumed level of metabolism. Fluctuations were greater in unshorn sheep.3. Pulse rate was lower during summer (60–100 for unshorn and 63–100 for shorn sheep) than in winter (90–130 for unshorn and 90–115 for shorn sheep). It tended to increase with a rise in ambient temperature, especially during winter and spring. A lower pulse rate accompanied a rise in environmental temperature, during summer. The slowest pulse rate of 42 per minute was observed during summer in the hot dry area.4. The pulse rate of both groups increased with a rise in rectal temperature, particularly at low ambient temperatures. At comparable rectal temperatures, a higher average pulse rate was observed in shorn sheep during winter and spring. With elevated summer temperatures, equal pulse rates were noted in both groups of equal rectal temperatures. Since the rectal temperatures of the shorn exceeded that of unshorn sheep, in high environmental temperatures, and in the sun, their pulse rate under these conditions was also higher.5. The differences in pulse rate between the two groups appeared to reflect the combined effects of metabolic rate, body temperature and the vasomotor activity, all of which vary with season and environmental temperatures.

EFFECTS OF THE TEMPERATURE OF THE ENVIRONMENT AND THE DRINKING WATER ON THE BODY TEMPERATURE AND WATER CONSUMPTION OF SHEEP

1962 ◽  
Vol 42 (1) ◽  
pp. 1-8 ◽  
Author(s):  
C. B. Bailey ◽  
R. Hironaka ◽  
S. B Slen
Keyword(s):  
Drinking Water ◽  
Body Temperature ◽  
Water Intake ◽  
Water Consumption ◽  
Environmental Temperature ◽  
The Body ◽  
Average Temperature ◽  
Subcutaneous Tissues ◽  
Environmental Temperatures ◽  
Reduced Water

Temperatures in the rumen, rectum, and subcutaneous tissues of four sheep receiving [Formula: see text] pounds of alfalfa hay per day were recorded at environmental temperatures of 15 °C. and −12 °C. The temperature of the drinking water was 20 °C. when the environmental temperature was 15 °C. and variously 0°, 10°, 20°, and 30 °C. during four different periods when the environmental temperature was −12 °C. At both environmental temperatures, the temperature in the rumen was higher than that in the rectum which, in turn, was higher than that in the subcutaneous tissues. The consumption of feed caused a transient increase in the temperature in the rumen and rectum while the consumption of water caused a transient decrease in the temperature in the rumen. A reduction in environmental temperature from 15 °C. to −12 °C. caused decreases in the temperatures in the rumen, rectum, and subcutaneous tissues, and reduced water intake from about 1600 to about 800 milliliters/day. At an environmental temperature of −12 °C., the temperature of the drinking water did not influence the amount of water consumed. It did, however, have an effect on body temperature because the average temperature in the rectum was slightly higher when the drinking water was 0 °C. than when it was 30 °C.

Effect of Environmental Temperature on Reaction of Mice to Parathion, an Anticholinesterase Agent

1956 ◽  
Vol 186 (1) ◽  
pp. 39-46 ◽  
Author(s):  
Anna M. Baetjer ◽  
Raymond Smith
Keyword(s):  
Body Temperature ◽  
Chemical Reactions ◽  
Environmental Temperature ◽  
Early Mortality ◽  
Intravenous Injections ◽  
Anticholinesterase Agent ◽  
Before And After ◽  
Rate Of Absorption ◽  
Rate Of Recovery ◽  
Environmental Temperatures

Mice were exposed to three environmental temperatures, 60°, 73° and 96°F, for 3 days before and after intraperitoneal injection with an anticholinesterase, parathion. The onset of deaths, rate of dying and rate of recovery were more rapid, the survival time of the fatal cases was shorter, and the mortality was higher at 96° than at 73°F. At 60°F, the onset of deaths was delayed, and the final but not the early mortality exceeded that at 73°F. Somewhat similar, though less significant, differences occurred with intravenous injections. Experiments with different pre- and postinjection temperatures showed that mortality varied directly with pre- and inversely with postinjection temperatures and latent period varied inversely with preinjection temperatures. For comparison, acetylcholine and neostigmine were injected intraperitoneally in mice at these three temperatures. The rate of dying and mortality were only slightly greater at 96° than at 73°F. At 60°F the onset of deaths was delayed, the animals died more slowly and the mortality was significantly lower than at 73°F. The results cannot be attributed to acceleration of chemical reactions with changes in body temperature but appear to be due to variations in rate of absorption and other factors.

scholarly journals Observations on the Temperature Regulation and Food Consumption of Honeybees (Apis Mellifera)

1958 ◽  
Vol 35 (4) ◽  
pp. 930-937 ◽  
Author(s):  
J. B. FREE ◽  
YVETTE SPENCER-BOOTH
Keyword(s):  
Apis Mellifera ◽  
Food Consumption ◽  
Temperature Regulation ◽  
Death Rate ◽  
Environmental Temperature ◽  
External Temperature ◽  
Sugar Syrup ◽  
The Difference ◽  
Environmental Temperatures

1. Bees have been kept in groups whose numbers ranged from 10 to 200 bees, at temperatures ranging from 0-40° C. 2. At 40° C. bees in groups of 200 had a higher death-rate than bees in smaller groups. At temperatures of 25-35° C. the death-rate was low and about the same in all groups . Below 25° C. the more bees in a group, the longer they survived. 3. The temperatures of all groups increased with that of their environment, the larger a group, the higher its temperature. The difference between the external temperature and that of the groups decreased with increase in the former until at 35 and 40° C. groups of all sizes were at or slightly below environmental temperature. 4. At temperatures from 20-40° C. the percentage of bees in a group that were clustering was directly related to the size of their group, bees in groups of 10 or 25 hardly clustering at all. At each temperature at 15° C. or below, about the same high percentage of bees clustered in all groups. 5. The amount of food (sugar syrup) consumed per bee increased with decrease in the environmental temperature. Very little water was drunk at environmental temperatures of 25° C. or lower but, at 35° C. and above, relatively enormous quantities were taken. 6. These results have been discussed especially in relation to information on the temperature regulation and food consumption of colonies in winter.

scholarly journals Thermal Performance Curves of Multiple Isolates of Batrachochytrium dendrobatidis, a Lethal Pathogen of Amphibians

2021 ◽  
Vol 8 ◽  
Author(s):  
Ciara N. Sheets ◽  
Deena R. Schmidt ◽  
Paul J. Hurtado ◽  
Allison Q. Byrne ◽  
Erica Bree Rosenblum ◽  
...  
Keyword(s):  
Thermal Performance ◽  
Growth Rates ◽  
Batrachochytrium Dendrobatidis ◽  
Abiotic Factors ◽  
Phenotypic Traits ◽  
Genetic Lineage ◽  
Multiple Traits ◽  
Performance Curves ◽  
Key Factor ◽  
Environmental Temperatures

Emerging infectious disease is a key factor in the loss of amphibian diversity. In particular, the disease chytridiomycosis has caused severe declines around the world. The lethal fungal pathogen that causes chytridiomycosis, Batrachochytrium dendrobatidis (Bd), has affected amphibians in many different environments. One primary question for researchers grappling with disease-induced losses of amphibian biodiversity is what abiotic factors drive Bd pathogenicity in different environments. To study environmental influences on Bd pathogenicity, we quantified responses of Bd phenotypic traits (e.g., viability, zoospore densities, growth rates, and carrying capacities) over a range of environmental temperatures to generate thermal performance curves. We selected multiple Bd isolates that belong to a single genetic lineage but that were collected across a latitudinal gradient. For the population viability, we found that the isolates had similar thermal optima at 21°C, but there was considerable variation among the isolates in maximum viability at that temperature. Additionally, we found the densities of infectious zoospores varied among isolates across all temperatures. Our results suggest that temperatures across geographic point of origin (latitude) may explain some of the variation in Bd viability through vertical shifts in maximal performance. However, the same pattern was not evident for other reproductive parameters (zoospore densities, growth rates, fecundity), underscoring the importance of measuring multiple traits to understand variation in pathogen responses to environmental conditions. We suggest that variation among Bd genetic variants due to environmental factors may be an important determinant of disease dynamics for amphibians across a range of diverse environments.

The influence of environmental temperature on the respiratory rhythm of dairy cattle in the tropics

1936 ◽  
Vol 26 (1) ◽  
pp. 36-44 ◽  
Author(s):  
Albert O. Rhoad
Keyword(s):  
Critical Temperature ◽  
Body Temperature ◽  
Environmental Temperature ◽  
Respiratory Rhythm ◽  
Farm Animals ◽  
Marked Influence ◽  
Established Fact ◽  
The Tropics ◽  
Physical And Chemical ◽  
Environmental Temperatures

That extreme environmental temperatures have a marked influence on metabolism is a well-established fact. The early investigators, Kellner, Atwater, Armsby and others, studied the energy income and output of farm animals in relation to various conditions of the environment, and from these studies the principles of basal metabolism, critical temperature, and physical and chemical regulation of body temperature have evolved.

EXERCISE AND TEMPERATURE REGULATION IN LEMMINGS AND RABBITS

1955 ◽  
Vol 33 (1) ◽  
pp. 428-435 ◽  
Author(s):  
J. S. Hart ◽  
O. Heroux
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Heat Production ◽  
Temperature Regulation ◽  
Thermal Equilibrium ◽  
Environmental Temperature ◽  
Body Temperatures ◽  
Temperature Changes ◽  
Extreme Cold ◽  
Environmental Temperatures

Oxygen consumption and body temperatures were determined in lemmings at environmental temperatures from 20 °C. to −10 °C. and in rabbits from 20 °C. to −50 °C. Body insulation indices were estimated as the ratio [Formula: see text]. In both species, increase in activity and decrease in temperature led to increases in oxygen consumption that were additive over the temperature range. Oxygen increments of work were independent of environmental temperature in the absence of progressive hypothermia. Work led to increases in body temperature at the upper environmental temperatures and to decreases in body temperature at the lower temperatures. In extreme cold, rabbits became progressively hypothermic during work and there was a decline in oxygen consumption. Body temperatures started to fall at environmental temperatures 18 °C. higher in working than in resting rabbits. Insulation was lower in working than in resting animals. During exercise there appears to be a readjustment of body temperature, insulation, and heat loss until thermal equilibrium is established. The regulation of heat production, within limits, seems to be independent of body-temperature changes during exercise.

The effect of rising environmental temperatures (35°–95° F.) On thyroid 131I release rate of holstein, brown swiss and jersey heifers

1960 ◽  
Vol 54 (3) ◽  
pp. 421-426 ◽  
Author(s):  
H. D. Johnson ◽  
A. C. Ragsdale
Keyword(s):  
Body Temperature ◽  
Release Rate ◽  
Environmental Temperature ◽  
Statistical Significance ◽  
Brown Swiss ◽  
Breed Differences ◽  
Two Temperatures ◽  
Control Body ◽  
Environmental Temperatures ◽  
Temperature Correlations

1. There were many distinct, consistent, individual differences in the thyroid activity of several of the animals used in this study. Graphic indications of breed differences were present at several high temperatures, and statistical analyses supported differences between the Jerseys raised at each temperature and the other two corresponding breeds. The Jerseys displayed higher rates. In no instances were there thyroid 131I release rate differences between Holsteins and Brown Swiss.2. There was a negative correlation between thyroid 131I release rate and temperature for each breed raised at each temperature. Correlations for the 50° F. animals were statistically significant below the 0·05 level of probability and for the 80° F. animals they were significant below the 0·01 level. As the environmental temperature increased from 35° to 80° F. there was a gradual decrease in thyroid 131I release rate. Above 80° F. there was a sharp decline in thyroid 131I activity.3. Within the range of environmental temperatures from 35° to 70° F. the animals raised at 80° F. displayed thyroid release rates higher than those of the animals raised at 50° F. At 80° and 90° F. the 50° F. Jerseys exhibited higher activity. The Jersey differences approached statistical significance. At the lower temperatures graphic differences between the Brown Swiss and the Holsteins raised at the two temperatures appeared to be present, but they were not generally supported by statistical analysis.4. At temperatures of 80° F. and above, when regulatory mechanisms could not control body temperature, both groups showed considerable rises in body temperature concomitant with decreases in thyroid 131I activity and TDN consumption. The 80° F. group showed a rise less sharp than that of the 50° F. group.

scholarly journals Body Temperature Frequency Distributions: A Tool for Assessing Thermal Performance in Endotherms?

2021 ◽  
Vol 12 ◽  
Author(s):  
D.L. Levesque ◽  
J. Nowack ◽  
J.G. Boyles
Keyword(s):  
Body Temperature ◽  
Thermal Performance ◽  
Core Body Temperature ◽  
Ground Squirrels ◽  
Body Temperatures ◽  
Frequency Distributions ◽  
Biologically Relevant ◽  
Performance Curves ◽  
Continuous Body ◽  
Core Body

There is increasing recognition that rather than being fully homeothermic, most endotherms display some degree of flexibility in body temperature. However, the degree to which this occurs varies widely from the relatively strict homeothermy in species, such as humans to the dramatic seasonal hibernation seen in Holarctic ground squirrels, to many points in between. To date, attempts to analyse this variability within the framework generated by the study of thermal performance curves have been lacking. We tested if frequency distribution histograms of continuous body temperature measurements could provide a useful analogue to a thermal performance curve in endotherms. We provide examples from mammals displaying a range of thermoregulatory phenotypes, break down continuous core body temperature traces into various components (active and rest phase modes, spreads and skew) and compare these components to hypothetical performance curves. We did not find analogous patterns to ectotherm thermal performance curves, in either full datasets or by breaking body temperature values into more biologically relevant components. Most species had either bimodal or right-skewed (or both) distributions for both active and rest phase body temperatures, indicating a greater capacity for mammals to tolerate body temperatures elevated above the optimal temperatures than commonly assumed. We suggest that while core body temperature distributions may prove useful in generating optimal body temperatures for thermal performance studies and in various ecological applications, they may not be a good means of assessing the shape and breath of thermal performance in endotherms. We also urge researchers to move beyond only using mean body temperatures and to embrace the full variability in both active and resting temperatures in endotherms.

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