O. G. Dely szerk.: Vertebrata Hungarica 15. (Budapest, 1974)
Topál, Gy.: Field Observation on Oriental Bats. Sex Ratio and reproduction 83-94. o.
Concerning its reproductive cycle I had only April and May observations in Vietnam. The 2 females caught in May were not gravid, while those examined in April were pregnant with the exception of 3 from a total of 38. The nonpregnant specimens came from Hanoi(36), Mai lam(30) and Yen so(35). In these cases there was either no conception, or reabsorption of fetus have occured. One of these animals had the sings of some illness in the maxillary bone, while the other non-gravid female had teeth strongly worn, thus it probably was very old. It is interesting to observe the number of embryos. One embryo was found in 3 females, in each case the fetus was in the left horn of the uterus, while the usual right side one was missing. Thus here probably a partial reabsorption took place. The latter 3 females came from Hanoi(36), Mai lam(30), and Xuan dinh(31). It has to be mentioned that all of them had strongly worn teeth, which shows that they belonged to the old age group. I found twins in 16 females with fetuses in both horns of the uterus, while tehere were 15 cases of triplets, that is, two fetuses in the right horn and one in the left horn of uterus. If age groups are considered here, 3 embryos were find only in 35 per cent of the old age group with well worn teeth, while in 52 per cent of the young age group with less worn or unworn teeth. There are indications in the literature as quoted by ASDELL (1964) on the occurence of triplets of this species in Japan. Greatest length of the embryos varied from 2. 5 to 10.0 mm. between April 25 to 29. The existing differences are probably due to different dates of conception. I did not find any correlation between the number of embryos and their growthrates, one could have thought that in case of triplets the growth-rate was lower. In Hanoi (36) I found a dead juvenile aged about three weeks on June 1. This also would point to a birth time in early May. Pipistrellus mimus WROUGHTON, 1899 I found mixed colonies of this bat in Calcutta(22) (the numbers of males and females were as foUows: 1-3 on November 24-27, 3-7 on December 5-6, and 5-3 on December 17) and in Barkalikapur(25) 2 males and 2 females on May 7. In the contrary, by netting I could collect exceptionally males (2, 1, 4) at Nalbani Salt Lakes(24) near Calcutta in November, January, and April. This was probably because of differences in behaviour of sexes. I have some rather interesting data concerning the reproduction of this species. A female collected in Calcutta (22) was gravid and had embryos of 9 mm. long in both horns of uterus on November 27. At the same locality I caught 7 females, in one of them 2 embryos-both were 13 mm. long - found on December 5 and 6. At the same time I also found 2 juveniles with 10.5 mm. forearms, and most of the adult females had swollen and reddish uterus. The 3-4 mm. long testes of the males also seem to proove a certain degree of sexual activity. In Calcutta (22) among the collected 3 females on December 17 none was pregnant. The 2 females caught in Barkalikapur(25) were nongravid on May 7, there at the same time I also found a young male with 24.1mm. forearm-length. One could suppose that it might have been born at the end of March or at the beginning of April. Finally, again in Calcutta(22) I collected 2 juveniles - about ten days old - with forearm-length of 14 mm., while another - cca. 5 days old with 10.1 mm. long forearm on September 20. Though these observations are somewhat sparse, my data contradict those of BROSSÉT (1962/b, d) on the same species from the western parts of India, while they are in accordance with PHILLIPS' (1922) observations made in Ceylon. Taking these into account one could conclude that the reproduction of this extremely common species is taking place all the year round on the whole area of its
