The butterfly Papilio xuthus detects visual motion using chromatic contrast.
Many insects' motion vision is achromatic and thus dependent on brightness rather than on colour contrast. We investigate whether this is true of the butterfly Papilio xuthus, an animal noted for its complex retinal organization, by measuring head movements of restrained animals in response to moving two-colour patterns. Responses were never eliminated across a range of relative colour intensities, indicating that motion can be detected through chromatic contrast in the absence of luminance contrast. Furthermore, we identify an interaction between colour and contrast polarity in sensitivity to achromatic patterns, suggesting that ON and OFF contrasts are processed by two channels with different spectral sensitivities. We propose a model of the motion detection process in the retina/lamina based on these observations.
Department of Evolutionary Studies of Biosystems, School of Advanced Sciences, Sokendai (The Graduate University for Advanced Studies), Shonan Village, Hayama, Kanagawa 240-0193, Japan stewart@soken.ac.jp.
Finlay J
FJ
Stewart
Department of Evolutionary Studies of Biosystems, School of Advanced Sciences, Sokendai (The Graduate University for Advanced Studies), Shonan Village, Hayama, Kanagawa 240-0193, Japan.
Michiyo
M
Kinoshita
Department of Evolutionary Studies of Biosystems, School of Advanced Sciences, Sokendai (The Graduate University for Advanced Studies), Shonan Village, Hayama, Kanagawa 240-0193, Japan.
Kentaro
K
Arikawa
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D002080:Butterflies / Q000502:physiology*; D003116:Color; D003118:Color Perception / Q000502:physiology; D009039:Motion Perception / Q000502:physiology; D012160:Retina / Q000502:physiology
butterfly; colour; motion; optomotor; photoreceptor