Metabolic characteristics and body composition in house finches: effects of seasonal acclimatization |
| |
Authors: | T P O'Connor |
| |
Institution: | (1) Department of Biology, University of Michigan, 48109-1048 Ann Arbor, MI, USA;(2) Present address: Department of Physiology, School of Medicine, University of California, 90024-1751 Los Angeles, CA, USA |
| |
Abstract: | House finches (Carpodacus mexicanus) from the introduced population in the eastern United States were examined to assess metabolic characteristics and aspects of body composition associated with seasonal acclimatization. Wild birds were captured during winter (January and February) and late spring (May and June) in southeastern Michigan. Standard metabolic rates did not differ seasonally, but cold-induced peak metabolic rate was 28% greater in winter than late spring. The capacity to maintain elevated metabolic rates during cold exposure (thermogenic endurance) increased significantly from an average of 26.1 to 101.3 min in late spring and winter, respectively. House finches captured in the late afternoon during winter had twice as much stored fat as those during late spring. Both the wet mass and lean dry mass of the pectoralis muscle, a primary shivering effector, were significantly greater during winter. The seasonal changes in peak metabolism and thermogenic endurance demonstrate the existence and magnitude of metabolic seasonal acclimatization in eastern house finches. Increased quantities of stored fat during winter appear to play a role in acclimatization, yet other physiological adjustments such as lipid mobilization and catabolism are also likely to be involved.Abbreviations
bm
body mass(es)
-
MR
metabolic rate(s)
-
MR
peak
peak metabolic rate(s)
-
SMR
standard metabolic rate(s) |
| |
Keywords: | Avian fat metabolism Peak metabolism Thermogentic endurance Thermoregulation Finch Carpodacus mexicanus |
本文献已被 SpringerLink 等数据库收录! |
|