| 研究課題/領域番号 |
17F17720
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| 研究機関 | 総合研究大学院大学 |
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研究代表者 |
蟻川 謙太郎 総合研究大学院大学, 先導科学研究科, 教授 (20167232)
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| 研究分担者 |
NAGLOO NICOLAS 総合研究大学院大学, 先導科学研究科, 外国人特別研究員
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| 研究期間 (年度) |
2017-07-26 – 2019-03-31
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| キーワード | single cell recording / photoreceptor / spectral sensitivity / polarization sensitivity / tracking / phototaxis / orientation / tethered flight |
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| 研究実績の概要 |
I trained in single cell electrophysiological recordings and achieved consistent penetration of retinal photoreceptors by the end of 2017/08. We used single cell recordings to measure the spectral and polarisation sensitivity of 300 photoreceptors in the Chestnut Tiger Parantica sita. These receptors were sensitive to ultraviolet (UV), blue (B), and green (G) light. UV and B receptors were all maximally sensitive to vertically polarised light (0°) while G receptors were sensitive to a range of e-vectors (45°, 90°, and 135°). A custom script was developed to semi-automate the analysis of spectral and polarisation measurements in current and future single cell recordings.
We also investigated the wavelength dependence of phototactic behaviour during free-flight. Two cameras were setup orthogonally and the 3D flight trajectories of butterflies were tracked and analysed under different light conditions. P. sita demonstrated strong positive phototaxis towards light abundant in short wavelength, while no phototaxis was observed under light abundant in long wavelengths.
We visited University of Wuerzburg, Germany, and collaborated with Dr. Basil el Jundi to build a flight simulator for studying orientation during flight. The setup has been successfully built and flight behaviour of tethered P. sita can now be investigated to ask questions about navigation during migratory flight. The setup can also be used to investigate multiple facets of flight behaviour in response to visual and non-visual cues across butterfly species in the field and in lab conditions.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
The research plan is on track and will produce at least one publication on the visual system of the Chestnut Tiger butterfly Parantica sita. A very thorough electrophysiological dataset has been collected in a timely manner. The visual system of this species is being investigated on various fronts and will produce a comprehensive understanding of how this animal sees the world. We have engaged with international researchers who are experts in the study of navigation and are currently in process of enabling several behavioural paradigms which will allow for a deeper study of visually mediated behaviour in this migratory species.
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| 今後の研究の推進方策 |
Last year, we measured the spectral and polarisation sensitivities of the retinal photoreceptors of Parantica sita. We found that there is an unexpected variation in the spectral sensitivity of long-wavelength receptors. Dye-injection after recording can allow us to examine the factors making this variation (e.g. cell screening, filtering pigments, etc.). The experiments will also be useful to determine how different photoreceptor types are distributed across the eye. Furthermore, we will use electron microscopy to study possible variation in the photoreceptor structure within and among ommatidia.
We will also study visually-mediated behaviours of P. sita using a flight simulator system. During the visit to the University of Wuerzburg this year, we had discussions about the method using the simulator with several experts there. The combination of electrophysiology with behavioural experiments will be powerful to investigate how visual cues are used during flight. Attendance at the International Congress of Neuroethology 2018 will also provide great exposure to the research community and increase the outreach of our work.
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