Changes in progesterone and testosterone during the breeding season of thelarge-footed myotis Myotis moluccarum (Microchiroptera : Vespertilionidae)

The reproductive biology of the large-footed myotis, Myotis moluccarum, was studied during the annual breeding season in southeast Queensland, Austral ia. Previous research has shown the species to be polyoestrous and monotocc ous, producing two consecutive young with some degree of synchrony in late October to early November and again in late January to early February. Horm onal data was collected and observations of the female reproductive tract m ade in order to ascertain the reproductive cycle of this species. In July, when females were not pregnant, progesterone concentrations were 1.9 +/- 0. 9 ng/ml. During the two gestation periods, progesterone concentrations incr eased progressively until late pregnancy at the end of October through to e arly November and again in late January to early February. During the lates t stages of pregnancy, progesterone concentrations of 69.9 +/- 18.7 ng/ml w ere reached. It is suggested that a plasma progesterone concentration in ex cess of about 8 ng/ml indicates pregnancy in this species. Plasma testoster one concentration in males reached a peak of 43.1 +/- 9.81 ng/ml in July, a nd was then variable until December when levels declined significantly to 2 .0 +/- 1.7 ng/ml.