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Avian thermoregulation in the heat: efficient evaporative cooling allows for extreme heat tolerance in four southern hemisphere columbids.
J Exp Biol 2016; 219(Pt 14):2145-55JE

Abstract

Birds show phylogenetic variation in the relative importance of respiratory versus cutaneous evaporation, but the consequences for heat tolerance and evaporative cooling capacity remain unclear. We measured evaporative water loss (EWL), resting metabolic rate (RMR) and body temperature (Tb) in four arid-zone columbids from southern Africa [Namaqua dove (Oena capensis, ∼37 g), laughing dove (Spilopelia senegalensis, ∼89 g) and Cape turtle dove (Streptopelia capicola, ∼148 g)] and Australia [crested pigeon (Ocyphaps lophotes), ∼186 g] at air temperatures (Ta) of up to 62°C. There was no clear relationship between body mass and maximum Ta tolerated during acute heat exposure. Maximum Tb at very high Ta was 43.1±1.0, 43.7±0.8, 44.7±0.3 and 44.3±0.8°C in Namaqua doves, laughing doves, Cape turtle doves and crested pigeons, respectively. In all four species, RMR increased significantly at Ta above thermoneutrality, but the increases were relatively modest with RMR at Ta=56°C being 32, 60, 99 and 11% higher, respectively, than at Ta=35°C. At the highest Ta values reached, evaporative heat loss was equivalent to 466, 227, 230 and 275% of metabolic heat production. The maximum ratio of evaporative heat loss to metabolic production observed in Namaqua doves, 4.66, exceeds by a substantial margin previous values reported for birds. Our results support the notion that cutaneous evaporation provides a highly efficient mechanism of heat dissipation and an enhanced ability to tolerate extremely high Ta.

Authors+Show Affiliations

DST-NRF Centre of Excellence at the Percy FitzPatrick Institute, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa aemckechnie@zoology.up.ac.za.DST-NRF Centre of Excellence at the Percy FitzPatrick Institute, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa.Department of Zoology, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031, South Africa.Department of Biology, University of Massachusetts, Amherst, MA 01003, USA.UNM Biology Department, University of New Mexico, MSC03-2020, Albuquerque, NM 87131-0001, USA.UNM Biology Department, University of New Mexico, MSC03-2020, Albuquerque, NM 87131-0001, USA.School of Animal & Veterinary Sciences, University of Adelaide, Roseworthy Campus, SA 5371, Australia.UNM Biology Department, University of New Mexico, MSC03-2020, Albuquerque, NM 87131-0001, USA.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

27207640

Citation

McKechnie, Andrew E., et al. "Avian Thermoregulation in the Heat: Efficient Evaporative Cooling Allows for Extreme Heat Tolerance in Four Southern Hemisphere Columbids." The Journal of Experimental Biology, vol. 219, no. Pt 14, 2016, pp. 2145-55.
McKechnie AE, Whitfield MC, Smit B, et al. Avian thermoregulation in the heat: efficient evaporative cooling allows for extreme heat tolerance in four southern hemisphere columbids. J Exp Biol. 2016;219(Pt 14):2145-55.
McKechnie, A. E., Whitfield, M. C., Smit, B., Gerson, A. R., Smith, E. K., Talbot, W. A., ... Wolf, B. O. (2016). Avian thermoregulation in the heat: efficient evaporative cooling allows for extreme heat tolerance in four southern hemisphere columbids. The Journal of Experimental Biology, 219(Pt 14), pp. 2145-55. doi:10.1242/jeb.138776.
McKechnie AE, et al. Avian Thermoregulation in the Heat: Efficient Evaporative Cooling Allows for Extreme Heat Tolerance in Four Southern Hemisphere Columbids. J Exp Biol. 2016 07 15;219(Pt 14):2145-55. PubMed PMID: 27207640.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Avian thermoregulation in the heat: efficient evaporative cooling allows for extreme heat tolerance in four southern hemisphere columbids. AU - McKechnie,Andrew E, AU - Whitfield,Maxine C, AU - Smit,Ben, AU - Gerson,Alexander R, AU - Smith,Eric Krabbe, AU - Talbot,William A, AU - McWhorter,Todd J, AU - Wolf,Blair O, Y1 - 2016/05/19/ PY - 2016/02/05/received PY - 2016/05/11/accepted PY - 2016/5/22/entrez PY - 2016/5/22/pubmed PY - 2017/8/10/medline KW - Body temperature KW - Columbiformes KW - Cutaneous evaporative water loss KW - Hyperthermia KW - Passeriformes KW - Respiratory evaporative water loss SP - 2145 EP - 55 JF - The Journal of experimental biology JO - J. Exp. Biol. VL - 219 IS - Pt 14 N2 - Birds show phylogenetic variation in the relative importance of respiratory versus cutaneous evaporation, but the consequences for heat tolerance and evaporative cooling capacity remain unclear. We measured evaporative water loss (EWL), resting metabolic rate (RMR) and body temperature (Tb) in four arid-zone columbids from southern Africa [Namaqua dove (Oena capensis, ∼37 g), laughing dove (Spilopelia senegalensis, ∼89 g) and Cape turtle dove (Streptopelia capicola, ∼148 g)] and Australia [crested pigeon (Ocyphaps lophotes), ∼186 g] at air temperatures (Ta) of up to 62°C. There was no clear relationship between body mass and maximum Ta tolerated during acute heat exposure. Maximum Tb at very high Ta was 43.1±1.0, 43.7±0.8, 44.7±0.3 and 44.3±0.8°C in Namaqua doves, laughing doves, Cape turtle doves and crested pigeons, respectively. In all four species, RMR increased significantly at Ta above thermoneutrality, but the increases were relatively modest with RMR at Ta=56°C being 32, 60, 99 and 11% higher, respectively, than at Ta=35°C. At the highest Ta values reached, evaporative heat loss was equivalent to 466, 227, 230 and 275% of metabolic heat production. The maximum ratio of evaporative heat loss to metabolic production observed in Namaqua doves, 4.66, exceeds by a substantial margin previous values reported for birds. Our results support the notion that cutaneous evaporation provides a highly efficient mechanism of heat dissipation and an enhanced ability to tolerate extremely high Ta. SN - 1477-9145 UR - https://www.unboundmedicine.com/medline/citation/27207640/Avian_thermoregulation_in_the_heat:_efficient_evaporative_cooling_allows_for_extreme_heat_tolerance_in_four_southern_hemisphere_columbids_ L2 - http://jeb.biologists.org/cgi/pmidlookup?view=long&pmid=27207640 DB - PRIME DP - Unbound Medicine ER -