Body Temperature Measurement Reveals the Reproductive Profile of Female Apodemus speciosus under Laboratory and Field Conditions

Abstract. This study illustrated body temperature (Tb) fluctuation during reproduction and discussed the effectiveness of measuring Tb for predicting the reproductive profile of female Apodemus speciosus both under laboratory and field conditions. Tb fluctuation was monitored for four breeding events in the laboratory and for three in the field. Individual variation in Tb fluctuation during reproduction was larger in the field than in the laboratory, while its temporal pattern was clearer in the field than in the laboratory. Tb fluctuating patterns according to the progress of the reproductive stage were similar between the laboratory and the field. Daily mean Tb increased after the start of pregnancy, decreased during late pregnancy, rapidly increased after parturition, and remained higher through the lactation period. In particular, the following three characteristics should be apparent indices of parturition: increase of daily mean Tb and daily minimum Tb in early pregnancy, decrease of daily max Tb and daily mean Tb in late pregnancy, and increase of daily max Tb at the day of parturition. These results indicate that implanting small-sized loggers enables us to obtain a representative pattern of Tb fluctuation and to predict the reproductive profile of female A. speciosus, both under laboratory and field conditions.