Most studies on bats in Taiwan concentrate in taxonomy, reproduction, activity patterns, and behaviors. However, researchers seldom focus to understand the patterns and functions of bat echolocation in Taiwan. Using a sophisticated Anabat II bat detector system, I was able to collect echolocation calls of bat species including Pipistrellus abramus, Miniopterus schreibersii, Rhinolophus monoceros, and Hipposideros terasensis in southern Taiwan.
Between these four bat species, R. monoceros has the highest frequency and P. abramus has the lowest frequency of echolocation calls. The echolocation calls that used by P. abramus belong to FM/CF type, with the maximum frequency at 53.30¡Ó5.30¡]mean ¡ÓS.D.¡^kHz, the minimum frequency at 46.74¡Ó1.94 kHz, the duration time at 5.97¡Ó1.53 msec, the frequency range at 6.55¡Ó4.29 kHz, and the frequency change rate at 2.65¡Ó2.21 kHz/msec. The echolocation calls that used by M. schreibersii belong to FM/CF type, with the maximum frequency at 65.12¡Ó12.24 kHz, the minimum frequency at 49.71¡Ó1.48 kHz, the duration time at 3.62¡Ó2.06 msec, the frequency range at 15.42¡Ó11.79 kHz, and the frequency change rate at 9.52¡Ó7.95 kHz/msec. The echolocation calls that used by H. terasensis belong to CF/FM type, with the maximum frequency at 68.16¡Ó0.86 kHz, the minimum frequency at 61.50¡Ó8.72 kHz, the duration time at 11.27¡Ó4.88 msec, the frequency range at 6.66¡Ó8.87 kHz, and the frequency change rate at 4.67¡Ó3.19 kHz/msec. The echolocation calls that used by R. monoceros belong to FM/CF/FM type, with the maximum frequency at 112.55¡Ó1.65 kHz, the minimum frequency at 89.57¡Ó18.03 kHz, the duration time at 34.30¡Ó9.13 msec, the frequency range at 22.98¡Ó17.75 kHz, and the frequency change rate at 7.70¡Ó4.20 kHz/msec.
R. monoceros¡]duty cycle 65 %¡^and H. terasensis ¡]duty cycle 39 %¡^are the high duty cycle bats. P. abramus¡]duty cycle 12 %¡^ and M. schreibersii¡]duty cycle 11 %¡^are the low duty cycle bats. High duty cycle bats have more stable maximum frequency of echolocation calls than low duty cycle bats. Low duty cycle bats have more stable minimum frequency of echolocation calls than that of high duty cycle bats. I compared the differences in echolocation calls emitted by these four bat species. I used the Dumcam¡¦s multiple-range test to confirm these echolocation calls have significant differences (p¡Õ0.05) in their maximum frequency, minimum frequency, frequency change rate, frequency range and duration of time. Similarly, I also used these five variables to run canonical discriminate analysis. The Mahalanobis distance¡¦s between pair of species varied from 12.01 (P. abramus A type and H. terasensis) to 197.80 (P. abramus A type and R. monoceros); all distances were statistically significant (p<0.01). These results confirm the fact that bats¡¦ echolocation calls can be used to clearly identify individual species, which is not only possible but also practicable. However, considering the possibilities of some habitat influence and geological/genetic difference, using echolocation for identification species should be done more cautiously.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0813101-103617 |
| Date | 13 August 2001 |
| Creators | Chao, Nien-Min |
| Contributors | none, G. Agoramoorthy, none |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0813101-103617 |
| Rights | unrestricted, Copyright information available at source archive |
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