Seasonal metabolic acclimatization varies in direction and magnitude among populations of an afrotropical Passerine bird

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dc.contributor.author Noakes, Matthew J.
dc.contributor.author Wolf, Blair O.
dc.contributor.author McKechnie, Andrew E.
dc.date.accessioned 2017-05-03T08:49:23Z
dc.date.issued 2017-03
dc.description.abstract Avian metabolic responses demonstrate considerable diversity under fluctuating environmental conditions, a well-studied example being the seasonal upregulation of basal metabolic rate (BMR) and summit metabolism (Msum) in temperate species experiencing harsh winters. Fewer studies have examined seasonal metabolic acclimatization in subtropical or tropical species. We investigated seasonal metabolic variation in an Afrotropical ploceid passerine, the white-browed sparrow-weaver (Plocepasser mahali; ∼47 g), at three sites along a climatic gradient of approximately 77C in winter minimum air temperature (Ta). We measured Msum (n ≥ 10 per site per season) in a helox atmosphere, BMR of the same birds at thermoneutrality (Ta ≈ 307C), and resting metabolic rates at 57C ≤ Ta ≤ 207C. Patterns of seasonal adjustments in BMR varied among populations in a manner not solely related to variation in seasonal Ta extremes, ranging from BMR ∼52% higher in winter than in summer to no seasonal difference. Greater cold tolerance was found in a population at a colder desert site, manifested as higher Msum (∼25% higher) and lower helox temperature at cold limit values compared with a milder, mesic site. Our results lend support to the idea that greater variance in the pattern of seasonal metabolic responses occurs in subtropical and tropical species compared with their temperatezone counterparts and that factors other than Ta extremes (e.g., food availability) maybe important in determining the magnitude and direction of seasonal metabolic adjustments in subtropical birds. en_ZA
dc.description.department Visual Arts en_ZA
dc.description.embargo 2018-03-31
dc.description.librarian am2017 en_ZA
dc.description.sponsorship The DST-NRF Centre of Excellence at the Percy FitzPatrick Institute and the University of Pretoria. en_ZA
dc.description.uri http://www.press.uchicago.edu/ucp/journals/journal/pbz.html en_ZA
dc.identifier.citation Noakes, MJ, Wolf, BO & McKechnie, AE 2017, 'Seasonal metabolic acclimatization varies in direction and magnitude among populations of an afrotropical Passerine bird', Physiological and Biochemical Zoology, vol. 90, no. 2, pp. 178-189. en_ZA
dc.identifier.issn 1522-2152 (print)
dc.identifier.issn 1537-5293 (online)
dc.identifier.other 10.1086/689030
dc.identifier.uri http://hdl.handle.net/2263/60175
dc.language.iso en en_ZA
dc.publisher University of Chicago Press en_ZA
dc.rights © 2017 by The University of Chicago en_ZA
dc.subject Acclimatization en_ZA
dc.subject Hypothermia en_ZA
dc.subject Metabolic diversity en_ZA
dc.subject Summit metabolism en_ZA
dc.subject Basal metabolic rate (BMR) en_ZA
dc.subject Subtropical bird en_ZA
dc.title Seasonal metabolic acclimatization varies in direction and magnitude among populations of an afrotropical Passerine bird en_ZA
dc.type Article en_ZA


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