The breeding biology of Miniopterus schreibersi blepotis (Termminck) (Chiroptera) in north-eastern NSW.

Abstract

The essential features of reproduction in the bent-winged bat (M. s. blepotis) in eastern Australia between latitudes 28 and 32°S. are as follows: Spermatogenesis is initiated in late November and December and the testes reach maximum development during April, those of yearling males not attaining the size reached in older individuals. Spermatozoa are abundant in the epididymides from May to mid-July with some males retaining a limited store through the winter. Most copulations occur during the period May-June and pregnancy ensues at once with retarded embryonic development through the early months till about mid-September. Females do not become pregnant in their first year. Litter size is one. Parturition occurs during December and early January at maternity colonies which are formed through October and November by females from a number of surrounding cave and mine colonies. Such colonies reform at the same locality each year and may comprise more than 10,000 adult females. The young are born naked with forearms of about 15.75 mm and, although flying at 7 weeks, do not reach adult proportions till nearly 10 weeks old. Adult females are nursing young throughout this period. Once the juveniles become independent the adult females leave the maternity colonies and through late March a mass exodus of juveniles occurs so that the colony is deserted early in April. Many juveniles return to the maternity colony temporarily when it is re-established in the spring following the season of their birth.