色弁別学習を用いたスナダコとマダコの色覚比較 [in Japanese] Color Discrimination Conditioning in Two Octopus Octopus aegina and O. vulgaris [in Japanese]
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感光色素を一種類しかもたないタコ類は色盲とされる。これを行動実験で検証するために, スナダコ5個体とマダコ7個体を用いて色覚を確かめる学習実験を行った。供試個体を負刺激球(白球あるいは灰色球)と同時呈示した青球(直径25mm, 反射スペクトルのλ<SUB>max</SUB>=460nm)に触れてから餌を摂るよう条件付けた後, 負刺激球を明度が段階的に異なる灰色球に換えて移調試験を行った。移調試験では, スナダコは灰色球の明度にかかわらず有意に高頻度で青球を選択し, 色覚をもつ可能性が示された。マダコは灰色球の明度によって選択球が変わり, 色盲であると結論された。
In order to investigate the color vision in Octopoda, color discrimination conditioning and transposition tests were done with two octopuses, Octopus aegina and O. vulgaris in tanks. The animals were trained to discriminate by touch between blue (25mm in diameter, reflectance λ<SUB>max</SUB>=460nm) and white or light shaded balls (negative balls) for a food reward. The balls were presented simultaneously in front of a shelter wherein each animal resided. After the completion of the conditioning, the negative balls were substituted with ones of different shades of gray (G1 to G5 in the order of reflectance), and transposition tests were done to examine the possibility of darkness-based discrimination. In the transposition tests, O. aegina showed correct responses at 70-100% to the blue ball irrespective of the shades of grey employed, implying the possession of color vision. O. vulgaris changed the choosing response with the shades of gray employed, indicating the darkness-based choosing and lack of color vision; biased to blue at G1, random at G2, biased to gray at G3 and G4 which were darker than the blue, and biased to blue at G5 which was much darker than the blue.
- NIPPON SUISAN GAKKAISHI
NIPPON SUISAN GAKKAISHI 67(1), 35-39, 2001-01-15
The Japanese Society of Fisheries Science