Spectral sensitivity of single photoreceptors and color vision in the stingless bee, Melipona quadrifasciata (original) (raw)
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Color distance derived from a receptor model of color vision in the honeybee
Biological Cybernetics, 1987
A model calculation is presented for investigating the domain between the two well-examined fields of color vision in the bee, i.e. choice behavior with respect to color stimuli, and photoreceptor physiology. Based on the properties of the receptors, the model explains quantitatively the results obtained in color discrimination experiments. The model predicts curved lines which connect the loci of most similar color stimuli in the receptor plane and makes quantitative predictions about the magnitude of the Bezold-Abney hue shift. A measure for color difference is derived from the number of the just-noticeabledifference (jnd) steps determined by the noise thresholds of the photoreceptor cells.
Arthropod-Plant Interactions, 2008
It has long been assumed that bees cannot see red. However, bees visit red flowers, and the visual spectral sensitivity of bees extends into wavelengths to provide sensitivity to such flowers. We thus investigated whether bees can discriminate stimuli reflecting wavelengths above 560 nm, i.e., which appear orange and red to a human observer. Flowers do not reflect monochromatic (single wavelength) light; specifically orange and red flowers have reflectance patterns which are step functions, we thus used colored stimuli with such reflectance patterns. We first conditioned honey bees Apis mellifera to detect six stimuli reflecting light mostly above 560 nm and found that bees learned to detect only stimuli which were perceptually very different from a bee achromatic background. In a second experiment we conditioned bees to discriminate stimuli from a salient, negative (un-rewarded) yellow stimulus. In subsequent unrewarded tests we presented the bees with the trained situation and with five other tests in which the trained stimulus was presented against a novel one. We found that bees learned to discriminate the positive from the negative stimulus, and could unambiguously discriminate eight out of fifteen stimulus pairs. The performance of bees was positively correlated with differences between the trained and the novel stimulus in the receptor contrast for the long-wavelength bee photoreceptor and in the color distance (calculated using two models of the honeybee colors space). We found that the differential conditioning resulted in a concurrent inhibitory conditioning of the negative stimulus, which might have improved discrimination of stimuli which are perceptually similar. These results show that bees can detect long wavelength stimuli which appear reddish to a human observer. The mechanisms underlying discrimination of these stimuli are discussed.
Detection of coloured stimuli by honeybees: minimum visual angles and receptor specific contrasts
Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology, 1996
Honeybees Apis mellifera were trained to distinguish between the presence and the absence of a rewarded coloured spot, presented on a vertical, achromatic plane in a Y-maze. They were subsequently tested with different subtended visual angles of that spot, generated by different disk diameters and different distances from the decision point in the device. Bees were trained easily to detect bee-chromatic colours, but not an achromatic one. Chromatic contrast was not the only parameter allowing learning and, therefore, detection: α min, the subtended visual angle at which the bees detect a given stimulus with a probability P 0 = 0.6, was 5° for stimuli presenting both chromatic contrast and contrast for the green photoreceptors [i.e. excitation difference in the green photoreceptors, between target and background (green contrast)], and 15° for stimuli presenting chromatic but no green contrast. Our results suggest that green contrast can be utilized for target detection if target recognition has been established by means of the colour vision system. The green-contrast signal would be used as a far-distance signal for flower detection. This signal would always be detected before chromatic contrast during an approach flight and would be learned in compound with chromatic contrast, in a facilitation-like process.
Mechanisms, functions and ecology of colour vision in the honeybee
Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology, 2014
Research in the honeybee has laid the foundations for our understanding of insect colour vision. The trichromatic colour vision of honeybees shares fundamental properties with primate and human colour perception, such as colour constancy, colour opponency, segregation of colour and brightness coding. Laborious efforts to reconstruct the colour vision pathway in the honeybee have provided detailed descriptions of neural connectivity and the properties of photoreceptors and interneurons in the optic lobes of the bee brain. The modelling of colour perception advanced with the establishment of colour discrimination models that were based on experimental data, the Colour-Opponent Coding and Receptor Noise-Limited models, which are important tools for the quantitative assessment of bee colour vision and colour-guided behaviours. Major insights into the visual ecology of bees have been gained combining behavioural experiments and quantitative modelling, and asking how bee vision has influe...
Natural phototaxis and its relationship to colour vision in honeybees
Journal of Comparative Physiology A, 1985
1. Honeybees are positively phototactic when they leave a feeding place and start to fly back to the hive. The strength of this natural phototactic response in individually marked bees was measured without interfering with their foraging behaviour. 2. Absolute sensitivity of this phototactic response to a point light source is in the range of 8.3 ▪ 10 7 quanta s-1 for 537 nm. This corresponds to about 5 absorbed quanta in 28 green receptors over the integration time of 60 ms. 3. We conclude that the properties of the mono-polar cells or higher order visual interneurons rather than those of the photoreceptors control the intensity dependence of the response because the slopes (n) of the response intensity functions (R / log I) are steep (n: 1.0-2.65) and wavelength dependent. Blue light (439 nm) causes the steepest function. 4. The effect of residual light adaptation on the R / log I-function and the spectral sensitivity (S(λ)) is negligible under the experimental conditions chosen, since the time course of dark adaptation is fast (τ ≤ 1 min). 5. The blue and green receptors contribute about equally to the S(λ) of this natural phototactic response, the UV receptors somewhat less (Fig. 5). 6. Colour mixing experiments, used to test colour vision in phototaxis, reveal no significant deviation from a simple linear summation of the quantal fluxes, irrespective of the spectral mixture used. We conclude, therefore, that under the experimental conditions colour vision is very unlikely to play a role in the phototactic behaviour of the honeybee. 7. All our results (steep R/log I-functions, fast dark adaptation, S(λ) and the absence of colour vision) support to notion that the natural phototactic response is controlled by neuronal pooling, most likely in the lamina M1 monopolar cells.
Color constancy in the honeybee
The Journal of neuroscience : the official journal of the Society for Neuroscience, 1988
A multicolored display was illuminated by 3 bands of wavelengths corresponding to the maxima of the spectral sensitivities of the 3 types of photoreceptors found in the bee retina. The intensity of each band could be varied individually. The light fluxes emitted by the colored areas of the multicolored display were determined quantitatively. Free-flying honeybees were trained with sugar solution to choose one of the colored areas. The illumination was then changed in such a way that the light fluxes formerly emitted by the training area were now measured on another area. When the trained bees were tested under those conditions, they still chose the training area. The relative positions of the colored areas were changed in order to exclude learning of position. It is concluded that color vision in bees is, in a certain range, independent of the spectral content of the illumination. Model calculations show that the behavior observed in bees is consistent with the retinex theory (Land,...
Animal Behaviour, 2003
Floral shape is a visual cue used by pollinators to discriminate between competing flower species. We investigated whether discrimination is possible between closed shapes presenting the same colour and lacking a centrally presented fixation point. Free-flying honeybees, Apis mellifera L., had to discriminate between a solid square and a solid triangle of the same colour presented on the back walls of a Y-maze. Different colours were used to vary chromatic contrast and receptor-specific contrasts. Discrimination was possible whenever shapes presented contrast to the long wavelength receptor but was independent of chromatic contrast, overall intensity contrast or short and middle wavelength receptor contrast. We suggest that the bees used the edges of the closed shapes to solve the task. Bees failed when shapes were rotated, showing that a single shape edge was not sufficient for recognition.
Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology, 1999
Honeybees Apis mellifera detect coloured targets presented to the frontal region of their compound eyes using their colour vision system at larger visual angles (a > 15°), and an achromatic visual system based on the long-wave photoreceptor type at smaller visual angles (5°< a < 15°). Here we examine the capability of the dorsal, ventral and frontal regions of the eye for colour detection. The minimum visual angle a min at which the bees detect a stimulus providing both chromatic contrast and receptor-speci®c contrasts to the three receptor types varies for the dierent regions of the eye: 7.1 0.5°for the ventral region, 8.2 0.6°for the dorsal region and 4.0 0.5°for the frontal region. Flight trajectories show that when the target was presented in the horizontal plane, bees used only the ventral region of their eyes to make their choices. When the targets appeared dorsally, bees used the frontodorsal region. This ®nding suggests that pure dorsal detection of coloured targets is dicult in this context. Furthermore, a min in the ventral plane depends on receptor-speci®c contrasts. The absence of S-receptor contrast does not aect the performance (a min = 5.9 0.5°), whilst the absence of M-and L-receptor contrast sig-ni®cantly impairs the detection task. Minimal visual angles of 10.3 0.9°and 17.6 3°, respectively, are obtained in these cases. Thus, as for many visual tasks, the compound eye of the honeybee shows a regionalisation of colour detection that might be related to peripheral or central specialisations.