| We studied diet, echolocation calls and night emergence time of black-bearded tomb bat, Taphozous melanopogon (Emballonuridae) at yanqian village, Zhaoyang countryside, guilin city, guangxi Province, South China between June to September,2005 and June to October, 2006.We captured 5579 insects belonging to 17 orders (including spider) at bats'potential feeding areas. Among these prey taxa, Lepidoptera is the largest part (49.76%), followed by Coleoptera (12.18%), Dipptera (9.99%), Orthoptera (8.85%), Homoptera (6.77%), Hemiptera (4.87%), Odonata (2.7%), Hymenoptera (1.7%) and Trichoptera (1.06%). Other orders are less than 1%, such as Neuroptera (0.73%), Dermaptera (0.57%), Phasmida (0.29%), Blattaria (0.02%), Isoptera (0.01%), Spider (0.01%), Megaloptera (0.006%) and Mantodea (0.003%).As for monthly variation of potential prey taxa, the result shows that Lepidoptera is the largest portion during the period though with drastic variation, Dipptera, Homoptera and Orthoptera got to their highest portion in August while Lepidoptera decreased sharply at this period. The portion of Hemiptera increased gradually, compared to Coleoptera decreased slowly in the following month. Hymenoptera and Odonata kept the same portion during this period.A total of 344 fecal samples were collected and analyzed from the day-roost of the studied black-bearded tomb bats, and totally eight insect orders were found. Leidoptera is the most abundant order in the diet (65.67 %), followed by Hemiptera (19.42%), Diptera (11.06%), Coleoptera (1.67%), Orthoptera (0.65%), Odonata (1.05%), Hymenoptera (0.26%) and Neuroptera (0.22%).The diet of this species clearly showed monthly variation (X2 = 422.96, df = 7, P = 0.000 < 0.001) (Table3). Except Lepidoptera, no prey item > 50% of total frequency percentage among August and October, but Hemiptera accounted for > 50% frequency percentage in June and July, and Diptera accounted for > 50% frequency percentage in July only.The food abundance of T. melanopogon is analyzed using Shannon-Wiener Index and we found that it decreased gradually (5.63, 4.21, 2.65, 2.01 and 1.12 from June to October, respectively).The average body mass of T. melanopogon is 22.7 g with an average forearm length of 64.9 mm. T-test was carried out on the body mass and forearm length between sexes, and no significant difference (P > 0.05) on body mass was found between males (22.5±2.5 g) and females (22.9±2.1g). Similarly, the average forearm length of males (64.6±1.8 mm) is not significantly different (P> 0.05) than that of females (65.3±1.5 mm). The wing measurements of females are slightly larger than that of males, but the difference is not significant. Wings of the black-bearded tomb bat have a high aspect ratio, while wing loading is high, but wing tip shape index is low. This species is fallen into quadrant ?, indicating they probably fly fast and agile in open area and edge of vegetation.We recorded echolocation calls of T. melanopogon at hand-held and freely flying conditions, and we found that T. melanopogon usually produces low-intensity and low frequency modulated (FM) calls containing four harmonics, with most energy in the second or sometimes in the third harmonics in both these recording status. However, it is significant difference on the end of first harmonics, the beginning of the second harmonics, dominant frequency, call duration, inter-pulse and duty cycle (T-test,p < 0.05) at different recording conditions.Totally, we made 14 evening observation of bat emergence. On average, bats left the cave 31.7±16.6 min and end at 104.7±51.2 min after sunset (about 19:00 h, n = 14). However, bats left the cave significantly earlier (P = 0.024 < 0.05) in clear day (4.5±7.2 min) than in cloudy day condition (15.5±0.7 min). Difference in no rain days (27.7±16.1 min) than in shower days (34.0±14.0 min) is not significant (P = 0.512 > 0.05), and difference in no wind days (32.7±15.4 min) than in gentle breeze days (23.5±31.8 min) is not significant (P = 0.509 > 0.05) neither. Similarly, difference in no moon light days (30.3±17.5 min) and in lunar days (40.5±6.4 min) is not significant (P = 0.440 > 0.05), but the overall monthly effect on evening emergence is significant (P = 0.009 < 0.05). Time of evening emergence correlated with the time of sunset (r2 = 0.77, P = 0.000 < 0.01), but not significant in ending evening emergence (r2 = 0.39, P > 0.05). Rates at which T. melanopogon emerged varied at different times of the month. For example, rates of emergence (number of bats per minute) were low in May and June, but high in July and then declined sharply in August and September.In a word, we can provide some scientific information of T. melanopogon of ecological characteristics from its diet, echolocation calls and night emergence time.
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