Interspecific variation of thermoregulation between small migratory and resident passerines in Wenzhou.
Physiological adaptation arises from several fundamental sources of phenotypic variation. Most analyses of metabolic adaptation in birds have focused on the basal metabolic rate (BMR), the lower limit of avian metabolic heat production. In this study, we investigated thermoregulation in three passerine species; the yellow-billed grosbeak Eophona migratoria, white-rumped munia Lonchura striata and black-throated bushtit Aegithalos concinnus, in Wenzhou, China. Metabolic rate was measured using the closed-circuit respirometer containing 3.5 L animal chambers. Body temperature (Tb) was measured during metabolic measurements using a lubricated thermocouple. The minimum thermal conductance of these species was calculated by measuring their Tb and metabolic rates. The yellow-billed grosbeak remained largely normothermic, and the white-rumped munia and black-throated bushtit exhibited variable Tb at ambient temperatures (Ta). Mean metabolic rates within thermal neutral zone were 2.48±0.09 O2(mL)/g/h for yellow-billed grosbeaks, 3.44±0.16 O2(mL)/g/h for white-rumped munias, and 3.55±0.20 O2(mL)/g/h for black-throated bushtits, respectively. Minimum thermal conductance of yellow-billed grosbeak, white-rumped munia and black-throated bushtit were 0.13±0.00, 0.36±0.01, and 0.37±0.01 O2(mL)/g/h/℃, respectively. The ecophysiological characteristics of these species were:(1) the yellowbilled grosbeak had relatively high Tb and BMR, a low lower critical temperature and thermal conductance, and a metabolic rate that was relatively insensitive to variation in Ta; all of which are typical of cold adapted species and explain its broader geographic distribution; (2) the white-rumped munia and blackthroated bushtit had high thermal conductance, lower critical temperature, and relatively low BMR, all which are adapted to warm environments where there is little selection pressure for metabolic thermogenesis. Taken together, these data illustrate small migratory and resident passerines that exhibit the different characteristics of thermoregulation.
School of Life and Environmental Sciences, Wenzhou University, Wenzhou 325035, China.
Qing-Gang
QG
Qiao
School of Life and Environmental Sciences, Wenzhou University, Wenzhou 325035, China.
Hong-Ji
HJ
Liang
School of Life and Environmental Sciences, Wenzhou University, Wenzhou 325035, China.
Min-Lan
ML
Bai
School of Life and Environmental Sciences, Wenzhou University, Wenzhou 325035, China;Zhejiang Provincial Key Lab for Subtropical Water Environment and Marine Biological Resources Protection, Wenzhou 325035, China.
Wei-Hong
WH
Zheng
School of Life and Environmental Sciences, Wenzhou University, Wenzhou 325035, China;Zhejiang Provincial Key Lab for Subtropical Water Environment and Marine Biological Resources Protection, Wenzhou 325035, China. ljs@wzu.edu.cn.
Jin-Song
JS
Liu
D025041:Animal Migration; D000818:Animals; D001833:Body Temperature Regulation; D002681:China; D005260:Female; D008297:Male; D046109:Passeriformes / Q000378:metabolism / Q000502:physiology*; D013045:Species Specificity
Aegithalos concinnus; Basal metabolic rate; Body temperature; Eophona migratoria; Lonchura striata; Thermal conductance