Reproduction, growth and maturity in the black flying-fox, Pteropus alecto(Megachiroptera : Pteropodidae)

This paper reviews the timing of reproduction, growth rates and age at matu rity of the black flying-fox, Pteropus alecto. This species is found from S ulawesi, Indonesia, south to the central east coast of Australia. In northe rn Australia at 12 degrees S most young are born in January-March, in contr ast to October-November at 27 degrees S in eastern Australia, but a small p ercentage of young are born outside the major birth peaks in both areas. Th e birth peaks of P. alecto appear to be aligned with periods of maximum pla nt productivity, rather than day length. The plasticity of breeding season is likely to be an important factor enabling P. alecto to colonise areas fr om near the equator to 29 degrees S. Individual growth rates were calculated for 27 P. alecto. The weight growth rate of these animals was 2.40 +/- 3.14 g day(-1) (mean +/- s.d.), while g rowth rate of the forearm was 0.19 +/- 0.18 mm day(-1) (mean +/- s.d.). The growth rate of the forearm of females was significantly greater than for m ales (P = 0.08). From the mean forearm lengths of animals trapped, separate growth curves were developed for juvenile males (n = 566) and females (n = 610); these indicate that growth rate of females is about 8% higher than t hat of males. Primiparous females had a forearm length of 171.1 +/- 3.4 mm (mean +/- s.d.) (n = 5), which is achieved 15-17 months after birth, but ab out a third of females with forearm lengths of 160-170 mm have suckled youn g. Males mature at an age greater than females due to their slower growth r ate, a phenomenon known from other megachiropteran species.