Climatic adaptation in thermogenesis and thermal insulation in wood mice (Apodemus argenteus).
Wood mice (Apodemus argenteus) were trapped live at three different altitudes (below 1,000, 1,900, and 2,400 m) during a 1-year period (Feb. 1984-Jan. 1985). After remaining at the trapped locations for 10-14 days, they were transferred into a climatic chamber at an altitude of 610 m. Oxygen consumption (VO2) and colonic temperature (Tco) were measured at chamber temperatures (Ta) of five steps (30, 20, 10, 0, and -10 degrees C) in freely moving conditions. In response to Ta of 0 degrees C for the mice trapped in winter when their mean local habitat temperature (Te) were lower than 0 degrees C, there was a significant inverse correlation between VO2 and Te (r = -0.70, p less than 0.001) whereas no significant correlation (r = 0.23) was observed in the mice trapped in other seasons when Te was higher than 0 degrees C. The correlation between Tco and Te was significant (r = -0.66, p less than 0.001) over the entire range of Te. The pelt weight of the mice trapped at Te higher than 0 degrees C had a significant inverse correlation with Te (r = -0.65, p less than 0.001), but not in the mice trapped at Te lower than 0 degrees C. After measurement of VO2 and Tco at Ta of 0 degrees C, the mice who had lived in colder habitats (below 0 degrees C) showed 0% mortality, whereas the mortality of the populations which had lived in warmer habitats was 13%. These results suggest that, in wood mice, adaptation to severe cold is established by an enhanced thermogenesis and by an increased insulation of the pelt in moderate cold.
Department of Environmental Physiology, Shinshu University School of Medicine, Matsumoto, Japan.
Y
Y
Yanagidaira
G
G
Ueda
T
T
Motoyama
A
A
Sakai
M
M
Yonekawa
D000222:Adaptation, Physiological; D000273:Adipose Tissue / Q000032:analysis; D000531:Altitude; D000818:Animals; D001831:Body Temperature; D001833:Body Temperature Regulation; D002980:Climate; D005260:Female; D008297:Male; D051379:Mice / Q000378:metabolism*; D010101:Oxygen Consumption