scholarly journals Experimental evidence that hyperthermia limits offspring provisioning in a temperate-breeding bird

2020 ◽  
Vol 7 (10) ◽  
pp. 201589
Author(s):  
Simon Tapper ◽  
Joseph J. Nocera ◽  
Gary Burness
Keyword(s):  
Body Temperature ◽  
Heat Dissipation ◽  
Endurance Performance ◽  
Tachycineta Bicolor ◽  
Tree Swallows ◽  
Feeding Rates ◽  
Breeding Bird ◽  
Ambient Temperatures ◽  
Nestling Provisioning ◽  
Daily Exercise

In many vertebrates, parental care can require long bouts of daily exercise that can span several weeks. Exercise, especially in the heat, raises body temperature, and can lead to hyperthermia. Typical strategies for regulating body temperature during endurance exercise include modifying performance to avoid hyperthermia (anticipatory regulation) and allowing body temperature to rise above normothermic levels for brief periods of time (facultative hyperthermia). Facultative hyperthermia is commonly employed by desert birds to economize on water, but this strategy may also be important for chick-rearing birds to avoid reducing offspring provisioning when thermoregulatory demands are high. In this study, we tested how chick-rearing birds balance their own body temperature against the need to provision dependent offspring. We experimentally increased the heat dissipation capacity of breeding female tree swallows ( Tachycineta bicolor ) by trimming their ventral feathers and remotely monitored provisioning rates, body temperature and the probability of hyperthermia. Birds with an experimentally increased capacity to dissipate heat (i.e. trimmed treatment) maintained higher feeding rates than controls at high ambient temperatures (greater than or equal to 25°C), while maintaining lower body temperatures. However, at the highest temperatures (greater than or equal to 25°C), trimmed individuals became hyperthermic. These results provide evidence that chick-rearing tree swallows use both anticipatory regulation and facultative hyperthermia during endurance performance. With rising global temperatures, individuals may need to increase their frequency of facultative hyperthermia to maintain nestling provisioning, and thereby maximize reproductive success.

Temperature regulation

2017 ◽  
Author(s):  
Bareket Falk ◽  
Raffy Dotan
Keyword(s):  
Body Temperature ◽  
Children And Adolescents ◽  
Temperature Regulation ◽  
Heat Dissipation ◽  
Epidemiological Data ◽  
Skin Surface ◽  
Neutral Zone ◽  
Sweat Loss ◽  
Ambient Temperatures ◽  
Dry Heat

Under all but the most extreme environmental heat conditions, children control their body temperature (at rest and during exercise) as well as adults. Children, however, use a different thermoregulatory strategy. Compared with adults, children rely more on dry heat dissipation and less on evaporative cooling (sweating). Their larger skin surface-area relative to mass does put children at increasing disadvantage, relative to adults, as ambient temperatures rise above skin temperature. Similarly, they become increasingly disadvantaged upon exposure to decreasing temperatures below the thermo-neutral zone. Like adults, children inadvertently dehydrate while exercising in hot conditions and are often hypohydrated, even before exercise, and their core temperature rises considerably more than adults in response to a given fluid (sweat) loss, which may put them at higher risk for heat-related injury. However, epidemiological data show rates of both heat- and cold-related injuries among children and adolescents as similar or lower than at any other age.

scholarly journals Body temperature is a repeatable trait in a free-ranging passerine bird

2021 ◽  
Author(s):  
Simon Tapper ◽  
Joseph J. Nocera ◽  
Gary Burness
Keyword(s):  
Body Temperature ◽  
Radio Frequency Identification ◽  
Heat Dissipation ◽  
Passerine Bird ◽  
Molecular Structures ◽  
Tree Swallow ◽  
Ambient Temperatures ◽  
Animal Populations ◽  
Male Tree ◽  
Few Data

Body temperature (Tb) affects animal function through its influence on rates of biochemical and biophysical reactions, the molecular structures of proteins and tissues, and ultimately, organismal performance. Despite its importance in driving physiological processes, there are few data on how much variation in Tb exists within populations of organisms, and whether this variation consistently differs among individuals over time (i.e., repeatability of a trait). Here, using thermal radio-frequency identification implants, we quantified the repeatability of Tb, both in the context of a fixed average environment (∼21 °C) and across ambient temperatures (6 – 31 °C), in a free-living population of tree swallows (Tachycineta bicolor, n=16). By experimentally trimming the ventral plumage of a subset of female swallows (n=8), we also asked whether the repeatability of Tb is influenced by the capacity to dissipate body heat. We found that both female and male tree swallow Tb was repeatable at 21 °C (R=0.89 – 92), but female Tb was less repeatable than male Tb across ambient temperature (Rfemale=0.10, Rmale=0.58), which may be due to differences in parental investment. Trimmed birds had on average lower Tb than control birds (by ∼0.5 °C), but the repeatability of female Tb did not differ as a function of heat dissipation capacity. This suggests that trimmed individuals adjusted their Tb to account for the effects of heat loss on Tb. Our study provides evidence a first critical step toward understanding if Tb is responsive to natural selection, and for predicting how animal populations will respond to climatic warming.

scholarly journals Heat dissipation in subterranean rodents: the role of body region and social organisation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
František Vejmělka ◽  
Jan Okrouhlík ◽  
Matěj Lövy ◽  
Gabriel Šaffa ◽  
Eviatar Nevo ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Heat Dissipation ◽  
Ventral Surface ◽  
Body Region ◽  
Subterranean Rodents ◽  
Ambient Temperatures ◽  
Social Species ◽  
Body Regions ◽  
Body Heat ◽  
Solitary Species

AbstractThe relatively warm and very humid environment of burrows presents a challenge for thermoregulation of its mammalian inhabitants. It was found that African mole-rats dissipate body heat mainly through their venter, and social mole-rats dissipate more body heat compared to solitary species at lower temperatures. In addition, the pattern of the ventral surface temperature was suggested to be homogeneous in social mole-rats compared to a heterogeneous pattern in solitary mole-rats. To investigate this for subterranean rodents generally, we measured the surface temperatures of seven species with different degrees of sociality, phylogeny, and climate using infrared thermography. In all species, heat dissipation occurred mainly through the venter and the feet. Whereas the feet dissipated body heat at higher ambient temperatures and conserved it at lower ambient temperatures, the ventral surface temperature was relatively high in all temperatures indicating that heat dissipation to the environment through this body region is regulated mainly by behavioural means. Solitary species dissipated less heat through their dorsum than social species, and a tendency for this pattern was observed for the venter. The pattern of heterogeneity of surface temperature through the venter was not related to sociality of the various species. Our results demonstrate a general pattern of body heat exchange through the three studied body regions in subterranean rodents. Besides, isolated individuals of social species are less able to defend themselves against low ambient temperatures, which may handicap them if staying alone for a longer period, such as during and after dispersal events.

scholarly journals Influence of Ambient Temperature on Radiative and Convective Heat Dissipation Ratio in Polymer Heat Sinks

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2286
Author(s):  
Jan Kominek ◽  
Martin Zachar ◽  
Michal Guzej ◽  
Erik Bartuli ◽  
Petr Kotrbacek
Keyword(s):  
Heat Transfer ◽  
Ambient Temperature ◽  
Convective Heat ◽  
Heat Dissipation ◽  
High Surface ◽  
Heat Sinks ◽  
Fourth Power ◽  
Molding Process ◽  
Ambient Temperatures ◽  
University Of Technology

Miniaturization of electronic devices leads to new heat dissipation challenges and traditional cooling methods need to be replaced by new better ones. Polymer heat sinks may, thanks to their unique properties, replace standardly used heat sink materials in certain applications, especially in applications with high ambient temperature. Polymers natively dispose of high surface emissivity in comparison with glossy metals. This high emissivity allows a larger amount of heat to be dissipated to the ambient with the fourth power of its absolute surface temperature. This paper shows the change in radiative and convective heat transfer from polymer heat sinks used in different ambient temperatures. Furthermore, the observed polymer heat sinks have differently oriented graphite filler caused by their molding process differences, therefore their thermal conductivity anisotropies and overall cooling efficiencies also differ. Furthermore, it is also shown that a high radiative heat transfer leads to minimizing these cooling efficiency differences between these polymer heat sinks of the same geometry. The measurements were conducted at HEATLAB, Brno University of Technology.

scholarly journals Diurnal Body Temperature and Rate of Passage of Loggers in Lions

Animals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1388
Author(s):  
Ted Friend ◽  
Giulia Corsini ◽  
Vincent Manero ◽  
Raffaella Cocco
Keyword(s):  
Body Temperature ◽  
Time Frame ◽  
Heat Lamp ◽  
Future Studies ◽  
Ambient Temperatures ◽  
Diurnal Patterns ◽  
Data Loggers ◽  
The Mean ◽  
African Lions ◽  
Circadian Patterns

The documentation of diurnal patterns in body temperature in lions could be important because disruption of circadian patterns can be a useful measure of distress. This study quantified changes in body temperature of seven African lions (Panthera leo) at 5 min intervals during cold conditions from noon until the ingested body temperature loggers were expelled the next day. Thirteen loggers were fed to 11 lions during their daily noon feeding, while ambient temperatures were also recorded using six data loggers. The lions had continuous access to their dens and exercise pens during the day but were restricted to their heavily bedded dens that also contained a heat lamp from 23:00 until 08:00 the next day. Body temperatures averaged 37.95 ± 0.42 °C at 15:50, and 36.81 ± 0.17 °C at 06:50 the next day, 30 min before the first loggers passed from a lion, and were significantly different (t-test, t = 8.09, df = 6, p < 0.0003). The mean duration for the time of passage was 22 ± 2.69 (h ± SD), so future studies using the noninvasive feeding of temperature loggers need to consider that time frame.

Ambient temperature effects on physiological traits of white-tailed deer

1975 ◽  
Vol 53 (6) ◽  
pp. 679-685 ◽  
Author(s):  
J. B. Holter ◽  
W. E. Urban Jr. ◽  
H. H. Hayes ◽  
H. Silver ◽  
H. R. Skutt
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Energy Expenditure ◽  
Ambient Temperature ◽  
Temperature Effects ◽  
Temperature Changes ◽  
Wind Chill ◽  
Ambient Temperatures ◽  
Energy Equilibrium ◽  
Body Energy

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.

The costs of reproduction in tree swallows (Tachycineta bicolor)

1991 ◽  
Vol 69 (10) ◽  
pp. 2540-2547 ◽  
Author(s):  
Nathaniel T. Wheelwright ◽  
Joanna Leary ◽  
Caragh Fitzgerald
Keyword(s):  
Life History ◽  
Clutch Size ◽  
Brood Size ◽  
Life History Theory ◽  
Tachycineta Bicolor ◽  
Laying Date ◽  
Tree Swallows ◽  
Costs Of Reproduction ◽  
Return Rates ◽  
Trade Offs

We investigated the effect of brood size on nestling growth and survival, parental survival, and future fecundity in tree swallows (Tachycineta bicolor) over a 4-year period (1987–1990) in an effort to understand whether reproductive trade-offs limit clutch size in birds. In addition to examining naturally varying brood sizes in a population on Kent Island, New Brunswick, Canada, we experimentally modified brood sizes, increasing or decreasing the reproductive burdens of females by two offspring. Unlike previous studies, broods of the same females were enlarged or reduced in up to 3 successive years in a search for evidence of cumulative costs of reproduction that might go undetected by a single brood manipulation. Neither observation nor experiment supported the existence of a trade-off between offspring quality and quantity, in contrast with the predictions of life-history theory. Nestling wing length, mass, and tarsus length were unrelated to brood size. Although differences between means were in the direction predicted, few differences were statistically significant, despite large sample sizes. Nestlings from small broods were no more likely to return as breeding adults than nestlings from large broods, but return rates of both groups were very low. Parental return rates were also independent of brood size, and there was no evidence of a negative effect of brood size on future fecundity (laying date, clutch size). Reproductive success, nestling size, and survival did not differ between treatments for females whose broods were manipulated in successive years. Within the range of brood sizes observed in this study, the life-history costs of feeding one or two additional nestlings in tree swallows appear to be slight and cannot explain observed clutch sizes. Costs not measured in this study, such as the production of eggs or postfledging parental care, may be more important in limiting clutch size in birds.

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