-This review will focus on the relationships between sensory responses of bees and behavior. Sensory responsiveness constrains individual foraging plasticity and skews collective foraging decisions of colonies. We will concentrate on pollen, nectar, and water foraging behavior and will show that differences in the sucrose responsiveness of bees correlate with different behavioral roles, which supports the response threshold model of division of labor. We will also show how a colony's "allocation" of foragers into foraging roles results from individual differences in responsiveness to task-related stimuli and discuss hypotheses on the behavioral relevance of these differences.behavioral plasticity / sucrose responsiveness / foraging behavior / collective decision / response threshold model

Honey bee foragers were tested for their proboscis extension response (PER) to water and varying solutions of sucrose. Returning pollen and nectar foragers were collected at the entrance of a colony and were assayed in the laboratory. Pollen foragers had a significantly higher probability of responding to water and to lower concentrations of sucrose. Bees derived from artificially selected high- and low-pollen-hoarding strains were also tested using the proboscis extension assay. Returning foragers were captured and tested for PERs0 to 30% sucrose. Results demonstrated a genotypic effect on PERs of returnining foragers. The PERs of departing high- and low-strain foragers were consistent with those of returning foragers. The PERs were related to nectar and water reward perception of foragers. High strain bees were more likely to return with loads of water and lower concentrations of sucrose than foragers from low pollen strain. Low-strain bees were more likely to return empty. We identified a previously mapped genomic region that contains a variable quantitative trait locus that appears to influence sucrose response thresholds. These studies demonstrate a gene-brain-behavior pathway that can be altered as a consequence of colony-level selection for quantities of stored food.

ABSTRACT. Fixed honey‐bees were conditioned to a scent in a one‐trial learning paradigm. In contrast to free‐flying colour‐conditioned bees, fixed scent‐conditioned bees do not show a biphasic time dependence of the conditioned response. Small metal probes were used to cool localized areas of the antennal lobes, alpha‐lobes, and calyces of the mushroom bodies of the brain at various times after conditioning. Localized cooling impaired the formation of memory in all three structures. The susceptibility to impairment after conditioning lasted approximately 3 min in the antennal lobes, 7 min in the alpha‐lobes, and 10 min in the calyx area. It was possible to determine the influence of the contralateral hemisphere (relative to the learning antenna) by conditioning bees with only one antenna. No contralateral impairment was found in the antennal lobes; there were minor effects in the alphalobes; contralateral cooling led to reductions of the conditioned response only in the calyx area. The temperature dependence of memory impairment was different for the antennal lobes and the mushroom bodies (alpha‐lobes and calyces). The latter were most sensitive to cooling at 5°C. No correlation between cooling duration and impairment of memory was found in the antennal lobes, but there was a linear relation between impairment and cooling duration in the alpha‐lobes. Brief cooling (5 or 10 s) resulted in significant impairment of memory formation only in the calyx area. A series of control experiments proved that the impairment of memory is due to a reversible block of neural activity. It was possible to show that the impairment is specific for the three neural structures analysed, by cooling the lobula of the optic system at various times after conditioning. Lesions of the brain or application of KCl also resulted in time‐dependent reductions of the conditioned response. Cooling the entire animal at various times after conditioning led to similar memory impairment to that resulting from localized cooling of the alphalobes.

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Using the proboscis extension response we conditioned pollen and nectar foragers of the honey bee (Apis mellifera L.) to tactile patterns under laboratory conditions. Pollen foragers demonstrated better acquisition, extinction, and reversal learning than nectar foragers. We tested whether the known differences in response thresholds to sucrose between pollen and nectar foragers could explain the observed differences in learning and found that nectar foragers with low response thresholds performed better during acquisition and extinction than ones with higher thresholds. Conditioning pollen and nectar foragers with similar response thresholds did not yield differences in their learning performance. These results suggest that differences in the learning performance of pollen and nectar foragers are a consequence of differences in their perception of sucrose. Furthermore, we analysed the effect which the perception of sucrose reward has on associative learning. Nectar foragers with uniform low response thresholds were conditioned using varying concentrations of sucrose. We found significant positive correlations between the concentrations of the sucrose rewards and the performance during acquisition and extinction. The results are summarised in a model which describes the relationships between learning performance, response threshold to sucrose, concentration of sucrose and the number of rewards.