Limits...
Color Difference and Memory Recall in Free-Flying Honeybees: Forget the Hard Problem.

Dyer AG, Garcia JE - Insects (2014)

Bottom Line: Absolute conditioning allows for rapid learning, but color discrimination is coarse.In contrast, an independent group of 6 bees trained to saliently different colors (>0.14 hexagon units) did not experience any decay in memory retention with increasing time.This suggests that whilst the bees' visual system can permit fine discriminations, flowers producing saliently different colors are more easily remembered by foraging bees over several days.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Monash University, Clayton VIC 3800, Australia. adrian.dyer@rmit.edu.au.

ABSTRACT
Free-flying honeybees acquire color information differently depending upon whether a target color is learnt in isolation (absolute conditioning), or in relation to a perceptually similar color (differential conditioning). Absolute conditioning allows for rapid learning, but color discrimination is coarse. Differential conditioning requires more learning trials, but enables fine discriminations. Currently it is unknown whether differential conditioning to similar colors in honeybees forms a long-term memory, and the stability of memory in a biologically relevant scenario considering similar or saliently different color stimuli. Individual free-flying honeybees (N = 6) were trained to similar color stimuli separated by 0.06 hexagon units for 60 trials and mean accuracy was 81.7% ± 12.2% s.d. Bees retested on subsequent days showed a reduction in the number of correct choices with increasing time from the initial training, and for four of the bees this reduction was significant from chance expectation considering binomially distributed logistic regression models. In contrast, an independent group of 6 bees trained to saliently different colors (>0.14 hexagon units) did not experience any decay in memory retention with increasing time. This suggests that whilst the bees' visual system can permit fine discriminations, flowers producing saliently different colors are more easily remembered by foraging bees over several days.

No MeSH data available.


Related in: MedlinePlus

Spectral reflectance of the four Tonpapier (Baehr, Germany: code number shown) cards used as stimuli. The colour of the lines approximately matches the colour of the cards considering human trichromatic vision.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4592575&req=5

insects-05-00629-f001: Spectral reflectance of the four Tonpapier (Baehr, Germany: code number shown) cards used as stimuli. The colour of the lines approximately matches the colour of the cards considering human trichromatic vision.

Mentions: In Group 1 each bee was first provided with absolute conditioning with two color targets (CS+ size = 6 × 6 cm; 130 GSM Tonpapier No. 32, Baehr, Germany: see Figure 1 for spectral reflectance) for 30 trials, whilst two hangers additionally each presented a 6 × 6 cm neutral grey card (No. 81) that matched the background of the rotating screen and allowed for scoring of choice frequency visits to respective hangers. Absolute conditioning implies the visual system learns a target colour independent of other stimuli in a training situation, for example if a Y-maze contains a colour target on a grey background in one arm and the alternative arm only contains a grey background, then only the target colour is learnt [23]. The color distance between these stimuli was determined using a hexagon color model of bee vision [30] and was 0.14 hexagon units, which is a color bees can easily learn [31]. This first stage is essentially absolute conditioning of an easy task to establish bees could learn; indeed all six bees in this group were very accurate at this pre-training task (mean accuracy = 94.8% ± 7.3% s.d.). Following absolute conditioning, each bee then received two non-rewarded tests, each lasting for 30 landings, which were interspersed with a short refresher bout to encourage motivation. The first test presented the training target color and a novel yellow color (No. 12; color distance = 0.23) which confirmed that the bee had learnt the target color (accuracy = 95.8% ± 4.7% s.d.; 1 sample t-test, t = 23.978, p < 0.001); this yellow color was used in only the first test. The second test presented a perceptually similar target color (Tonpapier No. 37; color distance versus No. 32 = 0.06 hexagon units) and in this case bee choices for the target color were at chance levels (accuracy = 51.2% ± 6.6% s.d.; 1 sample t-test, t = 0.460, p = 0.665); thus the bees generalized these similar colors following absolute conditioning establishing the perceptual difficulty of this visual task for the main experiment.


Color Difference and Memory Recall in Free-Flying Honeybees: Forget the Hard Problem.

Dyer AG, Garcia JE - Insects (2014)

Spectral reflectance of the four Tonpapier (Baehr, Germany: code number shown) cards used as stimuli. The colour of the lines approximately matches the colour of the cards considering human trichromatic vision.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4592575&req=5

insects-05-00629-f001: Spectral reflectance of the four Tonpapier (Baehr, Germany: code number shown) cards used as stimuli. The colour of the lines approximately matches the colour of the cards considering human trichromatic vision.
Mentions: In Group 1 each bee was first provided with absolute conditioning with two color targets (CS+ size = 6 × 6 cm; 130 GSM Tonpapier No. 32, Baehr, Germany: see Figure 1 for spectral reflectance) for 30 trials, whilst two hangers additionally each presented a 6 × 6 cm neutral grey card (No. 81) that matched the background of the rotating screen and allowed for scoring of choice frequency visits to respective hangers. Absolute conditioning implies the visual system learns a target colour independent of other stimuli in a training situation, for example if a Y-maze contains a colour target on a grey background in one arm and the alternative arm only contains a grey background, then only the target colour is learnt [23]. The color distance between these stimuli was determined using a hexagon color model of bee vision [30] and was 0.14 hexagon units, which is a color bees can easily learn [31]. This first stage is essentially absolute conditioning of an easy task to establish bees could learn; indeed all six bees in this group were very accurate at this pre-training task (mean accuracy = 94.8% ± 7.3% s.d.). Following absolute conditioning, each bee then received two non-rewarded tests, each lasting for 30 landings, which were interspersed with a short refresher bout to encourage motivation. The first test presented the training target color and a novel yellow color (No. 12; color distance = 0.23) which confirmed that the bee had learnt the target color (accuracy = 95.8% ± 4.7% s.d.; 1 sample t-test, t = 23.978, p < 0.001); this yellow color was used in only the first test. The second test presented a perceptually similar target color (Tonpapier No. 37; color distance versus No. 32 = 0.06 hexagon units) and in this case bee choices for the target color were at chance levels (accuracy = 51.2% ± 6.6% s.d.; 1 sample t-test, t = 0.460, p = 0.665); thus the bees generalized these similar colors following absolute conditioning establishing the perceptual difficulty of this visual task for the main experiment.

Bottom Line: Absolute conditioning allows for rapid learning, but color discrimination is coarse.In contrast, an independent group of 6 bees trained to saliently different colors (>0.14 hexagon units) did not experience any decay in memory retention with increasing time.This suggests that whilst the bees' visual system can permit fine discriminations, flowers producing saliently different colors are more easily remembered by foraging bees over several days.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Monash University, Clayton VIC 3800, Australia. adrian.dyer@rmit.edu.au.

ABSTRACT
Free-flying honeybees acquire color information differently depending upon whether a target color is learnt in isolation (absolute conditioning), or in relation to a perceptually similar color (differential conditioning). Absolute conditioning allows for rapid learning, but color discrimination is coarse. Differential conditioning requires more learning trials, but enables fine discriminations. Currently it is unknown whether differential conditioning to similar colors in honeybees forms a long-term memory, and the stability of memory in a biologically relevant scenario considering similar or saliently different color stimuli. Individual free-flying honeybees (N = 6) were trained to similar color stimuli separated by 0.06 hexagon units for 60 trials and mean accuracy was 81.7% ± 12.2% s.d. Bees retested on subsequent days showed a reduction in the number of correct choices with increasing time from the initial training, and for four of the bees this reduction was significant from chance expectation considering binomially distributed logistic regression models. In contrast, an independent group of 6 bees trained to saliently different colors (>0.14 hexagon units) did not experience any decay in memory retention with increasing time. This suggests that whilst the bees' visual system can permit fine discriminations, flowers producing saliently different colors are more easily remembered by foraging bees over several days.

No MeSH data available.


Related in: MedlinePlus