| 研究課題/領域番号 |
25440236
|
|---|
| 研究種目 |
基盤研究(C)
|
| 研究機関 | 京都大学 |
|---|
研究代表者 |
デビッド ヒル 京都大学, 霊長類研究所, 研究員 (90594250)
|
|---|
| 研究期間 (年度) |
2013-04-01 – 2016-03-31
|
| キーワード | 社会システム / 森林コウモリ / 離合集散社会 / 口頭伝達 / 偏性的分散 / 再生実験 / コテングコウモリ / ねぐら行動 |
|---|
| 研究概要 |
- We collected wing tissue samples from 174 individuals for genetic analysis of fine-scale population dynamics. These included 64 bats caught in Yakushima between June and November, 54 bats caught in Horoka Tomamau, Hokkaido and 56 caught in Ashiu Research Forest, Kyoto-fu.
- Genetic analysis of samples from Yakushima revealed that pairs of kin-related females tended to be caught in the same location. Indications are that females are philopatric, but that more than 25% of males had dispersed from their natal area.
- Faecal samples were obtained from almost all bats caught. DNA analysis is being used to obtain information on dietary composition. Diet will be compared between the three different regions, between bats caught in natural forest and in conifer plantations, and between males and females. The DNA analysis of faecal samples is being done by collaborators at the University of Copenhagen, Denmark.
- Over 4,000 communication calls were recorded over 36 nights in summer and autumn in Yakushima using automated ultrasound recorders. These included both vocal responses to playback and unelicited calls. Recordings of almost 600 of the calls are of sufficient quality for acoustic analysis which will enable us to construct an ethogram of the vocal repertoire of this species. All recordings were also time-stamped so the data can be analysed for temporal and seasonal patterns in calling.
|
| 現在までの達成度 (区分) |
現在までの達成度 (区分)
3: やや遅れている
理由
In 2013 capture rates in Yakushima were much lower than in previous years making some of the proposed playback experiments impractical. Response rates were high enough for collection of samples for DNA analysis, but too low to yield sufficient data from behavioural experiments. Instead, an additional experiment was done in which the bats’ vocalisations were recorded through the night on 36 nights in two conditions: responses to periodic playback and in the absence of playback. This work produced a large collection of vocalisations that will allow a thorough description of the vocal repertoire, as well as temporal and seasonal patterns in call production. This will be the first study of its kind for non-captive bats.
Further work that was not in the original proposal was the collection of samples for DNA analysis from two additional sites: Horoka Tomamu Montane Forest Reserve in Hokkaido and Ashiu Research Forest in Kyoto-fu. This work was very successful, providing a substantial collection of tissue samples and faecal samples for DNA analysis from each site for comparison with Yakushima.
Good progress was also made in the laboratory with the genetic analysis of DNA data from Yakushima, building on preliminary work that was done in 2012. The results of this research were presented by Dr Jon Flanders (RA) in an oral paper at the International Bat Research Conference in Costa Rica in August 2013, and the manuscript is currently undergoing final edits before submission to a peer-reviewed international journal (probably “Conservation Genetics”) this summer.
|
| 今後の研究の推進方策 |
Playback experiments (originally planned for Years 1 and 2) in which the responses of bats are recorded using infrared video will be used to examine the influence of call type, call provenance and playback location on the bats’ behaviour.
In addition, females will be radio-tracked to establish locations of maternity roosts, size and composition of roosting groups and ranging areas. The aims of this work are to get further information on social dynamics and to establish whether responses to calls represent defence of the home range area from perceived intruders.
Socio-ecological approaches to the study of group-living in other orders of mammals, such as primates and carnivores, have attempted to explain inter- and intra-specific variation in characteristics such as group size, composition and kinship among group members in terms of environmental variation.
Although Murina ussuriensis is a forest-dwelling species throughout its distribution in Japan, its habitats include a variety of forest types from cool temperate deciduous forests in Hokkaido to warm temperate evergreen rainforests in Yakushima. It is also found in areas where much of the native forest has been replaced with single species conifer plantations there. Future work will assess whether any aspects of grouping patterns appear to be associated with these different habitat types.
We will also examine ecological variation between the sites in terms of dietary composition. Faecal samples have routinely been collected from captured bats since the project began. These will be used for DNA analysis of dietary composition.
|
| 次年度の研究費の使用計画 |
The original proposal for Year 1 included two Research Assistants: one to work in the field and the other in the laboratory. As explained in #3 above, the research plan had to be changed because capture rates of bats were low compared with previous years. This change meant that only one RA was required and he worked both in the field and in the lab. The plan to purchase equipment for PIT-tagging in Year 1 was postponed, also because of the low capture rates. These changes resulted in reductions in the actual costs for personnel, equipment and consumables. However, the revised research schedule also involved some additional costs, mostly in connection with travel by the PI for fieldwork to supplementary field sites in Hokkaido (one trip) and Ashiu Research Forest, Kyoto (two trips).
The original research plan for Year 2 included hiring just one RA for field work in the summer. The additional funds carried over from Year 1 will be used to hire a second RA to assist with fieldwork in Yakushima. This will increase our capture effort and should make it feasible to conduct the playback experiment originally planned for Year 1, as well as the research planned for Year 2, radio-tracking adult females to establish ranging areas and simultaneous radio-tracking of pairs. Employment of one RA will also continue into the winter months to carry out acoustic analysis of calls recorded in Years 1 and 2, describe the vocal repertoire of this species (call types and sequences of calls) and look for temporal, seasonal and regional difference in vocal behaviour.
|
