O. G. Dely szerk.: Vertebrata Hungarica 15. (Budapest, 1974)
Topál, Gy.: Field Observation on Oriental Bats. Sex Ratio and reproduction 83-94. o.
My Otis laniger (PETERS, 1871) Two males and 1 female were collected during their evening activity in the cave at Mamosmai(26) on November 17. Myotis longipes pOBSON, 1873) In contrary to many species of Myotis of the temperate regions, two South East Asian species showed no typical nursing colonies, i.e. the gatherings of females during pregnancy and parturition. So, in a huge population of this bat, numbering 5 thousands, the collected sample of 50 adult specimens showed roughly 1.8:1 ratio for males and females in Bum zov Cave (2) on June 9,while the sex ratio among 11 juveniles was 1.2:1. At the above locality I found 2 pregnant females along with 15 collected nonpregnant ones on June 9. Most of them were lactating. The embryos measured 18 mm. The 11 juveniles obtained had forearm-length of 14-23 mm. Myotis hasseltii (TEMMINCK, 1840) From the scattered data on this species observed in Vietnam one can draw similar conclusions on sex ratios to that of previous bat. In Yen so(35) I collected 2 males and a gravid female on April 18, in Xuan dinh(31) a female with newborn young, a gravid female and a male were together on April 28. It must be mentioned, however, that I found a colony of males (sample size 8) in Co loa (37) on April 16, while among a group of 8 there was only 1 female at the same locality on December 11. Most of the females observed at the localities near Hanoi (36) were gravid in the second half of April. In Yen so (35) a female had an embryo with a total length of 22 mm. on April 18. At the same place and on the same date I caught a female with a cca. two days old juvenile with forearm-length of 15 mm. In Xuan dinh(31) one of the 2 collected females had an embryo of 23 mm. length, while the other was a lactating one on April 28. Here I must mention that - hiding with these females - I found a sexually active male with enlarged testes. The fact that no regular nursing colonies exist, and that a sexually active male was found along with lactating or late pregnant females probably shows that their reproductive cycle differs from that of European Myotis species. In Co loa (37) I found a female in the company of 7 males on December 11. They were in a state of semi-torpidity without any sign of sexual activity. Pipistrellus pipistrellus bactrianus SATUNIN, 1905 In Srinagar(l) the females caught were gravid on May 26, 29, 30 and 31. Each of them had a single embryo in the right horn of the uterus. In 2 of them I found fetuses in early stage, while in those 2 I caught on May 29 and 31, the embryos were 5.3 and 4 mm. long respectively. Pipistrellus abramus (TEMMINCK, 1840) This bat species seems to be the the commonest one in and around Hanoi (36) and in towns of Vietnam . It is worthy to note, that females were always collected in groups from wall cracks and bamboo holes, e. g. from Mai lam (30), Yen so (35), Xuan dinh (31), Hanoi(36) and Thang toi(38) during April, while males probably were solitary as e. g. the specimen found in Co loa(37).
