AGE-RELATED VARIATION IN PHYSICAL AND REPRODUCTIVE CONDITION OF MALE DAUBENTON'S BATS (MYOTIS DAUBENTONII)

We studied age-related variation in body mass and epididymal distension in male Daubenton’s bats. Examination of data on epididymal distension in young of the year indicates that some reach sexual maturity by the year of birth, whereas others do so in their 2nd summer. Body mass and epididymal distension were positively correlated in young of the year and adults, suggesting that early sexual maturation and reproductive condition during later life are dependent on body condition. Older males tended to be heavier and in better reproductive condition than younger ones. Examination of our data suggests that physical and reproductive condition of males increase after the initial onset of fertility until 3 years of age. This late physical maturation is in line with other life-history traits characterizing long-lived bats as K-strategists among small mammals.