Control of metabolic rate is a hidden variable in the allometric scaling of homeotherms

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dc.contributor.authorChaui-Berlinck J.G.
dc.contributor.authorNavas C.A.
dc.contributor.authorMonteiro L.H.A.
dc.contributor.authorBicudo J.E.P.W.
dc.date.accessioned2024-03-13T01:44:02Z
dc.date.available2024-03-13T01:44:02Z
dc.date.issued2005
dc.description.abstractThe allometric scaling exponent of the relationship between standard metabolic rate (SMR) and body mass for homeotherms has a long history and has been subject to much debate. Provided the external and internal conditions required to measure SMR are met, it is tacitly assumed that the metabolic rate (B) converges to SMR. If SMR does indeed represent a local minimum, then short-term regulatory control mechanisms should not operate to sustain it. This is a hidden assumption in many published articles aiming to explain the scaling exponent in terms of physical and morphological constraints. This paper discusses the findings of a minimalist body temperature (Tb) control model in which short-term controlling operations, related to the difference between Tb and the set-point temperatures by specific gains and time delays in the control loops, are described by a system of differential equations of Tb, B and thermal conductance. We found that because the gains in the control loops tend to increase as body size decreases (i.e. changes in B and thermal conductance are speeded-up in small homeotherms), the equilibrium point of the system potentially changes from asymptotically stable to a centre, transforming B and Tb, in oscillating variables. Under these specific circumstances the very concept of SMR no longer makes sense. A series of empirical reports of metabolic rate in very small homeotherms supports this theoretical prediction, because in these animals B seems not to converge to a SMR value. We conclude that the unrestricted use of allometric equations to relate metabolic rate to body size might be misleading because metabolic control itself experiences size effects that are overlooked in ordinary allometric analysis.
dc.description.firstpage1709
dc.description.issuenumber9
dc.description.lastpage1716
dc.description.volume208
dc.identifier.doi10.1242/jeb.01421
dc.identifier.issn0022-0949
dc.identifier.urihttps://dspace.mackenzie.br/handle/10899/37875
dc.relation.ispartofJournal of Experimental Biology
dc.rightsAcesso Restrito
dc.subject.otherlanguageAllometry
dc.subject.otherlanguageBody temperature
dc.subject.otherlanguageControl
dc.subject.otherlanguageDynamic system
dc.subject.otherlanguageMetabolic rate
dc.titleControl of metabolic rate is a hidden variable in the allometric scaling of homeotherms
dc.typeArtigo de revisão
local.scopus.citations15
local.scopus.eid2-s2.0-18944383351
local.scopus.updated2024-05-01
local.scopus.urlhttps://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=18944383351&origin=inward
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