Seasonal changes in desert hamster Phodopus roborovskii breeding activity(In English)
Natalia Yu FEOKTISTOVA*,Ilya G. MESCHERSKY
S e v e r t s o v I n s t i t u t e o f E c o l o g y a n d E v o l u t i o n , R u s s i a n A c a d e m y o f S c i e n c e s , L e n i n s k i i p r . 3 3 , M o s c o w 1 1 9 0 7 1 , R u s s i a
Data on desert hamster Phodopus roborovskii<\i> winter activity and seasonal patterns of reproduction are scarce. During 9 years we maintain a colony of Desert hamsters under natural temperature and light regimes. These natural conditions suggest that the data on breeding activity may be in a good accordance with that in the wild. None of observed animals showed signs of torpor or hibernation in winter – even at about 40 °C below zero. The first peak of breeding (2.4 litters born per 10 pairs and 3.5 pups per litter in average) occurs in April and the second one (2.9–2.6 litters per 10 pairs and 3.9–3.6 pups per litter in average) in June–July. In autumn and early winter, the intensity of breeding declines to 0.1–0.4 litters per 10 pairs but does not cease completely. All adult males have visible testes and all adult females have opened vaginas entries through the year. The averaged males’ plasma level of testosterone, being maximal in summer, declines in autumn and early winter, but single hamsters keep their testosterone high even under shortest photoperiod and during cold months. In spring, average testosterone level significantly increases but does not reach summer values [Acta Zoologica Sinica 51(1): 1 -6, 2005].