Detection of coloured patterns by honeybees through chromatic and achromatic cues.
We asked whether the detection range of two-coloured centre-surround patterns differs from that of single-coloured targets. Honeybees Apis mellifera were trained to distinguish between the presence and absence of a single-coloured disc or a coloured pattern at different visual angles. The patterns presented colours which were either different in chromatic and L-receptor contrasts to the background, equal in chromatic but different in L-receptor contrasts, or vice-versa. Patterns with colours presenting only chromatic contrast were also tested. Patterns with higher L-receptor contrast in its outer than in its inner element were better detected than patterns with a reversed L-contrast distribution. However, both were detected worse than single-coloured discs of the respective colours. When the L-receptor contrast was the same for both elements, the detection range of the two-coloured and single-coloured targets was the same. Patterns whose colours lacked L-receptor contrast were detected just as single-coloured targets of the same colours. These results demonstrate that both chromatic and L-receptor contrasts mediate the detection of coloured patterns and that particular distributions of L-receptor contrast within a target are better detected than others. This finding is consistent with the intervention of neurons with centre-surround receptive fields in the detection of coloured patterns.
Hempel de Ibarra
N
N
Institut für Biologie--Neurobiologie, Freie Universität Berlin, Germany. nhempel@neurobiologie.fu-berlin.de
Giurfa
M
M
Vorobyev
M
M
D000818:Animals; D001516:Bees / Q000502:physiology*; D001522:Behavior, Animal; D003118:Color Perception / Q000502:physiology*; D005123:Eye / Q000648:ultrastructure; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010944:Plants