Eothenomys
miletus and Apodemus chevrieri
are typical species of small mammals inhabiting in Hengduan mountains
region. The characteristics of thermoregulation and thermogenesis of
two mammals were measured to search their physiological and ecological
characteristics of adaptations to this region in different seasons. All
results indicated: the body weight of E.
miletus and A. chevrieri in
summer was separately 47.29±0.73g, 32.74±0.54g, and their body weight
in winter was separately 39.28±0.61g, 31.70±0.76g; the thermal neutral
zones (TNZ) of E. miletus and
A. chevrieri in summer were
separately 25 ～32.5 oC and 25 ～30 oC, and their TNZ in winter were all of
22.5 ～ 27.5 oC; their basal metabolic rates (BMR) in
summer were respectively 3.76± 0.07 ml O2/g.h, 4.58±0.09 ml O2/g.h, and their BMR in winter were
respectively 4.46±0.04 ml O2/g.h, 5.23±0.01 ml O2/g.h; their maximum nonoshivering
thermogenesis (NST) in summer was respectively 5.70±0.18 ml O2/g.h, 7.12±0.31 ml O2/g.h, and their NST in winter was
respectively 6.67±0.05 ml O2/g.h, 7.42±0.04 ml O2/g.h; their NST scope (NST/BMR) in
summer was separately 1.52±0.05, 1.46±0.04, and their NST scope in
winter was separately 1.49±0.01, 1.42±0.01. Their thermogenic
characteristics and thermoregulatory styles possibly reflected features
of small rodents in Hengduan mountains region which have lower body
temperatures and NST scope, higher BMR, Cm and NST and could keep their
body temperatures stable in narrower ambient temperatures comparing
with other rodents. Body temperature, Cm BMR and NST of A. chevrieri were higher than these
of E. miletus. A. chevrieri could keep body
temperature stable in a wider range of ambient temperatures than E. miletus. NST scope of E. miletus was higher than it of A. chevrieri. Their TNZ and the
ambient temperature range in which they could keep C stable in winter
were narrower than these indexes in summer. The body temperature and
body weight in winter were lower comparing with the summer. The BMR,
F-value and NST maxin winter were significantly higher than the summer.
The TNZ in winter was shifted to the lower ambient temperature
comparing with the summer.
