2005 Fiscal Year Final Research Report Summary
Morphological and electrophysiological studies on the neural mechanism for visually guided distance estimation
| Project/Area Number |
16570064
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Animal physiology/Animal behavior
|
|---|
| Research Institution | KYUSHU UNIVERSITY |
|---|
Principal Investigator |
TOH Yoshihiro Kyushu University, Faculty of Science, Professor, 大学院・理学研究院, 教授 (60037265)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
OKADA Jiro Kyushu University, Faculty of Science, Research Associate, 大学院・理学研究院, 助手 (10284481)
YAMAWAKI Yoshifumi Kyushu University, Faculty of Science, Research Associate, 大学院・理学研究院, 助手 (80325498)
|
|---|
| Project Period (FY) |
2004 – 2005
|
| Keywords | tiger beetle / vision / stemma / distance sensitivity / praying mantis / hawk moth / compound eye / insect |
|---|
| Research Abstract |
Estimation of distance of an object is one of the important visual functions for wide variety of animals. Humans estimate an object distance using several cues such as binocular disparity and reference of apparent size with its absolute size in memory. Insects also estimate distance of an object. They can fly well without colliding with various obstacles by virtue of such abilities. However, the neural basis for distance estimation has not been examined in insects. In the present study the visual system was examined in three species of insects to see neural mechanisms for distance estimation.
The tiger beetle larva shows distinct visual behavior to moving objects. When prey approaches the larva in the tunnel, the larva jumps to snap at it. When an object moves beyond its jumping range, the larva always shows the escape response. In the present study responses of visual interneurons to moving objects close to or far from the larva were examined. Most neurons responded with similar patterns to both close and distant objects. But, a few neurons selectively responded to either near-by or distant objects only. Their morphology was visualized by dye filling after recordings. Their dendritic distribution appeared to be concerned with their function.
Distance sensitive visual interneurons also occurred in the optic neuropil of the praying mantis. Distance selective spike responses were recorded there, but impaled neurons have not been morphologically identified yet. The humming bird hawk moth is known to have high ability for distance estimation, because it extends a long proboscis hovering in front of a flower. In the present study a unique structure of the compound eye was observed in the hawk moth. Such design is considered to be concerned with distance estimation of this insect.
|
