2017 Fiscal Year Annual Research Report
Motion and color information processing in the Papilio visual system
| Project/Area Number |
17F17720
|
|---|
| Research Institution | The Graduate University for Advanced Studies |
|---|
Principal Investigator |
蟻川 謙太郎 総合研究大学院大学, 先導科学研究科, 教授 (20167232)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
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
|
|---|
| Project Period (FY) |
2017-07-26 – 2019-03-31
|
| Keywords | single cell recording / photoreceptor / spectral sensitivity / polarization sensitivity / tracking / phototaxis / orientation / tethered flight |
|---|
| Outline of Annual Research Achievements |
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.
|
| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
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.
|
| Strategy for Future Research Activity |
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.
|
