Population ecology of Formosan leaf-nosed bat (Hipposideros terasensis)
Date Issued
2004
Date
2004
Author(s)
Cheng, Hsi-Chi
DOI
zh-TW
Abstract
Abstract
The studies reported in this dissertation included three parts: (1) the annual and daily activity patterns of the Formosan leaf-nosed bat (Hipposideros terasensis), (2) the postnatal growth pattern of young Formosan leaf-nosed bats, and (3) the annual variation in colony size and composition of of Formosan leaf-nosed bat colonies.
Studies on the daily and annual activity patterns of the Formosan leaf-nosed bat were conducted at a non-breeding colony and a breeding colony in Nantou County between July 1995 and June 1996. The activity patterns of bats of these two colonies showed a similar trend throughout the year. Bats generally arrived at the roosts between late February and early March and left for hibernation in winter. No bat stayed in either roosts from December to next February. However, between March and November, the changes of sizes at these two colonies showed different patterns. In the non-breeding colony, bats arrived in February, and the number of individual reached a peak of more than 600 bats in March. Most bats left from nonbreeding roost in the following months untill September. On the other hand, the size of the breeding colony increased gradually from March to May, and the largest number of bats congrugated appeared in September and October (but < 100 bats). The number of bats decreased quickly in November to zero. Most bats in the breeding colony left their roost two months later than in the non-breeding colony. Daily activity pattern showed that the Formosan lea-nosed bats emerge at dusk and return to the roosts at dawn. The timing of activities was significantly correlated to the time of sunset and sunrise, as well as light intensity. Activity patterns of these two colonies were either unimodal or bimodal throughout the night in different months. The difference may be due to the breeding state of bats in the colonies or the weather condition. Finally, we found that Formosan leaf-nosed bat emergened at a much lower light intensity than did the other two bat species (Scotophilus kuhlii and Pipistrellus abramus) in Nantou County.
To examine the postnatal growth pattern of young Formosan leaf-nosed bats, changes in body mass, length of forearm, and length of the total epiphyseal gaps of young were recorded. Length of forearm and body mass of neonates 1-day old averaged 43.3 ± 2.7 mm and 15.9 ± 3.3 g, respectively. Length of forearm increased the fastest in the first week, but the rate of increase decreased thereafter until it reached a similar size to that of adults in the 6th week. Mean body mass of young also increased the fastest in the first week. By the third week, they achieved ca. 70% of the mean postpartum mass of adult females. Length of total epiphyseal gap increased to its maximum size at about 10 days after birth and subsequently decreased linearly before young bats were able to fly independently. The equation for estimating age based on length of forearm is valid when forearm length is £ 91 mm, whereas the equation for estimating age based on length of total epiphyseal gap is valid when forearm length is > 91 mm. These 2 equations make it possible to estimate the age of young H. terasensis between 1 to 44 days old. By applying the logistic model to derive the growth curves of length of forearm and the body mass for young H. terasensis, a growth constant of 0.114 was obtained for the increase in body mass. Subsequent monitoring suggested that male and female H. terasensis are capable of reaching sexual maturity in their first and second year, respectively. When compared to other bats, the growth rate of H. terasensis was faster than that of many tropical species, but was slower than that of most temperate species.
Three colonies of Formosan leaf-nosed bat, at Shuili, Chungliao I, and Chungliao II in Nantou County, central Taiwan, were monitored by both direct observations and mark-recapture for different periods between 1996 and 2000. The Shuili colony was mostly comprised of adult males. The size of this bachelor colony peaked in both Mar. and July~Aug., with about 400~700 individuals. The proportion of male bats at the Chungliao I colony was over 50% in most months except in Mar. At Chungliao II, however, the proportion of male bats was less than 30% almost year-round. Other members of the 2 colonies were mostly breeding females and their young. One or 2 peaks in numbers were found in these 2 breeding colonies in different years, with a maximum of 400~500 individuals at Chungliao I between July and Oct., and more than 2300 individuals at Chungliao II in Aug.~Sept. In winter, large numbers of hibernating bats were found only at Chungliao II. Birth and natal dispersal of the young and seasonal migration of adults contributed to temporal changes in size and composition of these colonies. Juvenile female bats showed higher fidelity to their natal roost than did males and bats of other ages.
Keywords：Hipposideridae, annual cycle, activity pattern, colony size, breeding colony, morphologic value, mark-recapture, sex ratio, fidelity, Taiwan
Subjects
年週期
葉鼻蝠科
生殖群集
捕捉標放
成長
性別比率
群集量
忠實度
活動模式
fidelity
Taiwan
Hipposideridae
annual cycle
activity pattern
colony size
sex ratio
mark-recapture
morphologic value
breeding colony
Type
other
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