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In their natural environments, most animals must learn about multiple kinds of rewards, both within and across contexts. Despite this, the majority of research on animal learning involves a single reward type. For example, bees are an important model system for the study of cognition and its ecological consequences, but nearly all research to date on their learning concerns a single reward, nectar (carbohydrates), even though foragers often simultaneously collect pollen (protein). Features of learning under more ecologically realistic conditions involving multiple reward types are thus largely unexplored. To address this gap, we compared performance on a colour-learning task when floral surrogates offered bumblebees, Bombus impatiens , a single type of floral reward versus multiple, nutritionally distinct rewards. In one experiment, bees learned a floral association with nectar either alone or while simultaneously collecting pollen. In a reciprocal experiment, bees learned a floral association with pollen either alone or while simultaneously collecting nectar. Bees that collected pollen while learning about nectar did not suffer any detriment to learning which flower colour offered nectar. However, this was not the case for the reciprocal task: collecting nectar impaired bees' ability to learn and remember associations between floral colour and pollen. Our findings offer new insight into how bees learn in relation to ecologically realistic rewards and how cognitive constraints may shape their behaviour under ecologically realistic foraging scenarios. [ABSTRACT FROM AUTHOR]

The learning capacities of males and females may differ with sex-specific behavioural requirements. Bumblebees provide a useful model system to explore how different lifestyles are reflected in learning abilities, because their (female but sterile) workers and males engage in fundamentally different behaviour routines. Bumblebee males, like workers, embark on active flower foraging but in contrast to workers they have to trade off their feeding with mate search, potentially affecting their abilities to learn and utilize floral cues efficiently during foraging. We used a serial colour-learning task with freely flying males and workers to compare their ability to flexibly learn visual floral cues with reward in a foraging scenario that changed over time. Male bumblebees did not differ from workers in both their learning speed and their ability to overcome previously acquired associations, when these ceased to predict reward. In all foraging tasks we found a significant improvement in choice accuracy in both sexes over the course of the training. In both sexes, the characteristics of the foraging performance depended largely on the colour difference of the two presented feeder types. Large colour distances entailed fast and reliable learning of the rewarding feeders whereas choice accuracy on highly similar colours improved significantly more slowly. Conversely, switching from a learned feeder type to a novel one was fastest for similar feeder colours and slow for highly different ones. Overall, we show that behavioural sex dimorphism in bumblebees did not affect their learning abilities beyond the mating context. We discuss the possible drivers and limitations shaping the foraging abilities of males and workers and implications for pollination ecology. We also suggest stingless male bumblebees as an advantageous alternative model system for the study of pollinator cognition. [ABSTRACT FROM AUTHOR]

Stress has complex effects on learning and memory, depending on both the type of stress and when the animal experiences it. Honeybees and bumblebees are agriculturally important pollinators for whom the effects of stress are extremely relevant. These pollinators are often transported long distances during which colonies experience severe physical disturbance, causing stress to individuals prior to their release for pollination. Under natural foraging conditions, bees are excellent at learning about the flowers they forage from, including associations between floral stimuli and rewards. However, it is not clear how stress might affect bees’ abilities to learn and remember floral features. Here we address the effects of acute stress on learning and memory in the bumble bee, Bombus impatiens . Using the Proboscis Extension Response (PER) protocol, we look at stress effects on learning and memory in three experiments. After being trained to a conditioned stimulus, we addressed: (1) the effect of 24 h and (2) 30 min of stress on the recall of this learned association and (3) the effect of stress on subsequently learning an association. We found that 24 h of stress after learning appeared to improve memory recall, and there was a trend in the same direction for 30 min of stress. However, bees that were stressed prior to learning an association did not differ from unstressed bees in their ability to learn or remember an association. Our finding that stress has effects on memory in the bumblebee could have implications for their use in behavioral experiments and for promoting the success of both managed and wild populations. [ABSTRACT FROM AUTHOR]

Bumblebees integrate cues associated with food that they experience within their nest. Both experienced and naïve workers rely on odours in the nectar collected by foragers and stored in honeypots to gain information about currently available food sources. The ability of workers to retain memories of these odours and to orient towards them when they leave the nest affects both foraging efficiency and food yield for the colony. In this study, we added sugar solution containing a floral scent (i.e. training scent) directly to empty honeypots within nests of Bombus impatiens in the absence of all other stimuli normally associated with successful foragers. To assess bee learning and memory, we quantified the effects of (a) the number of exposures to the training scent during conditioning, (b) the number of days elapsed post-conditioning (3 days vs. 6 days) and (c) bee age, on appetitive choice of the training scent relative to an unfamiliar scent. A high proportion of the bees of all ages (i.e. 74–80%) contacted the scented syrup we supplied briefly to colonies, with most contacting it once but some as many as 14 times. Most of the bees that may have experienced the training scent in the hive atmosphere but failed to contact a honeypot containing the scented sucrose solution (i.e. bees for which the training scent was familiar but unrewarded) exhibited no response to either the familiar or unfamiliar scent; the few that responded had no preference for either scent. More frequent contact with the scented sucrose increased the likelihood a bee would respond to the scent subsequently. Bees that contacted the scented nectar 1–4 times during conditioning preferred the rewarded odour when tested 3 days later, but after 6 days their scent choice was random, suggesting they retained no memory of it. In contrast, bees that contacted the scented nectar 5–14 times chose the rewarded odour over an unrewarded odour 23 of 24 times when tested 6 days after exposure. This is the first confirmation of social learning in B. impatiens. Our results highlight the importance of direct contact with scented nectar in honeypots and the strong long-term memory of a rewarded scent acquired through relatively brief but repeated exposure to it. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine whether a preference by flower-naïve bumblebees could be created or enhanced by manipulating variables relevant to food collection and to defense against predation. In two experiments, colonies of bumblebees ( Bombus impatiens ) were deprived of pollen, exposed to CO 2 , or neither. Choices of individual workers in a radial arm maze were monitored. In Experiment 1, both variables lead to a preference for corridors occupied by a conspecific bee. The effect was specific: no change in preference for corridors occupied by other objects (a coin and a piece of Styrofoam) was detected. In Experiment 2, radial and concentric patterns were used, both of which were unoccupied. Only pollen deprivation increased preference for radial stimuli, while CO 2 had no discernible effect. Preferences for visual patterns by bees leaving their colony for the first time are modulated by variables that affect the internal state of the bees in problem-specific ways. [ABSTRACT FROM AUTHOR]

Researchers of vertebrate navigation have investigated and debated intensely the existence of independent processes underlying spatial representation of environmental geometry and featural cues (e.g., landmarks). One of the most well-known behavioural instantiations of this dissociation originates from the differences in the way animals map locations in the surrounding environment with respect to the external cues such as boundaries or landmarks. Invertebrate researchers have joined this debate in the past few years, showing that insects can be trained to encode spatial locations using a variety of cues within small enclosures. In the present paper, we test insects in a non-rewarded, spontaneous navigation task. We observed bumblebees’ spatial navigation in response to the observed location of a conspecific, over manipulations of cue type and arena size. The results indicate that bumblebees spontaneously use both boundaries and features to guide their spatial behaviour. We discuss the similarities and differences in their behaviours to those of vertebrates and speculate on the implications of these findings. [ABSTRACT FROM AUTHOR]

Flexible division of labour is a key feature of social insects. Our understanding of individual response behaviour and how it is integrated into a functioning colony is still patchy. Most theoretical studies addressing this question are based on the assumption that workers have intrinsic and often fixed response thresholds for task-related stimuli. Here, we investigated the plasticity in worker fanning response behaviour in a bumblebee, Bombus terrestris. Using a temperature-controlled brood dummy, we first asked whether the fanning response is modulated by rate of temperature change. Second, we examined to what extent the fanning response is influenced by recent fanning experience. Our results show that the individual fanning response is modulated by both the rate of temperature increase and recent experience. Workers responded at lower temperatures and with a higher probability when the temperature of the brood dummy increased slowly compared with more rapid temperature increases. Workers that repeatedly responded to an increase in brood dummy temperature with fanning showed a significant decrease in their response thresholds, whereas the response thresholds of control workers that experienced the same treatment but did not gather fanning experience remained unchanged. The decrease in response threshold was pronounced when the time interval between two successive fanning events was less than 6h. When 16h or more separated fanning events, individual fanning responses returned to higher threshold levels. We suggest that experience-dependent modulation of response thresholds plays an important role in the behavioural differentiation of workers and the flexibility of insect colonies. [Copyright &y& Elsevier]

It is now recognized that many vertebrates and a few invertebrates show individual-specific consistency in their behaviour across time and context, sometimes in ways that can be paralleled with human personality. Our work aimed at assessing behavioural consistency in a social insect: the bumblebee Bombus terrestris. We focused on a behavioural dimension commonly used in personality studies: the response of an individual to novelty (neophilia/neophobia spectrum). We used a foraging paradigm to quantify individual bees’ response to novel flower colours and to assess the repeatability of this response over time. As for vertebrates, most individual bumblebees responded to a novel stimulus by increasing the time they spent investigating it compared to known stimuli. Using a new statistical approach, the consistency model, we found that individual bees tended to be consistent in their response to novelty over a few hours but were not consistent in their behaviour over 3 days. We conclude that for the neophilia/neophobia paradigm used here, bumblebee foragers do not fulfil the criteria for animal personality in the common sense of the term. Instead their behavioural response to novelty appears to be plastic, varying on a day to day basis. [ABSTRACT FROM AUTHOR]

Pollinators are confronted with spatial heterogeneity in floral resources. Acquiring information about their environment enables pollinators to exploit floral resources optimally, and hence strongly affects their fitness. Despite their evolutionary importance, spatial resource distribution and social information use have never been addressed in a plant–pollinator framework. We experimentally tested the effects of inadvertent social information (ISI) use (without or with an experienced demonstrator) in relation to spatial flower distribution (random or patchy) in foraging Bombus terrestris. We studied naïve bees'' associative learning when confronted with rewarding and nonrewarding flowers that differed slightly in colour, reproducing the natural mimicry of deceptive species. Naïve bees were more efficient foragers with than without a demonstrator in the patchy flower distribution, suggesting that they used ISI from conspecifics, probably in the form of social attraction at the patch scale. In the random flower distribution, however, ISI did not improve performance of naïve bees, and could not replace individual sampling. Analyses of nonrewarding intraspecific transitions indicate that the efficiency of naïve bees in deceptive species pollination was lowered when rewarding and nonrewarding inflorescences were patchily distributed and especially when bees relied on ISI. Thus, spatial flower distribution and ISI availability interact in determining pollinator behaviour, which has important consequences for plant community pollination. This suggests that bumblebees are adapted to exploit patchily distributed resources socially, a characteristic that might be exploited by deceptive plant species. By coupling behavioural and community ecology, this study offers promising perspectives for cognitive ecology studies in plant–pollinator interactions. [Copyright &y& Elsevier]

Determines the importance of female status and courtship behavior in predicting copulation in the bumblebee, Bombus terrestris. Ground and flight activity of the queen; Contributing factors that determine the copulation interaction between males and females; Effect of female repulse behavior on chance of copulation.

Studies the sperm transfer and potential competition between males over mating opportunities in bumblebees. Measurement of the duration of copulation; Deposition of `mating plug' into females; Implications of male selfishness to the ability of females to seek other mates.

Discusses the results of the magnitude of transfer and interference between two related learning events in bumblebees. Effect of the types of interactions in the value of learning; Control for transfer; Interference of learning new task with previously learned tasks; Control for interference; Sequential switching.

Tests the ability of bumblebees to form simple categories of floral colors. Discrimination of bees between rewarding and non-rewarding flowers; Recognition of novel members of learned categories; Ruling out of memorization and generalization based on similarity between floral types as the mechanisms underlying bees' behavior.

Presents a study of the relationship between bumble bee learning and flower morphology. Examination of the time required for bees to learn flower handling skills among nine plant species with varying flower morphology; Effects of the complexity of a flower's morphology; Influence of individual age and size in learning skill.

Tests the hypothesis that bumble bees' choice of flower species to forage on are the result of perceptual limitations and the demands of energetic efficiency. Discrimination between floral types; Learning rates.

Examines the performance of social species of bumblebee, Bombus bimaculatus, and solitary species of carpenter bee, Xylocopa virginica, in studies in which bees had to learn to discriminate between rewarding and non-rewarding flowers that differed in color. Similar levels of overnight memory retention in both species; Suggestion that social bees have better learning capabilities compared with solitary bees.

Presents a study which looked at the detection of visited flowers in a mixed community of bumblebees foraging on comfrey, Symphytum officinale, in souther England. Detailed information on the methodology used to conduct the study; Discussion based on the results of the study.

Compares three currencies which could be maximized during pollen collection by bumblebees foraging on different lupin species. Details on the types of animals which use the foraging technique; Findings of studies conducted; Methodology used in studies.

Presents information on a study which investigated the function and mechanism underlying a previously documented `mirror-image ambiguity' in foraging bumblebees. Construction of the mirror-images; What bees were trained to do; Materials and apparatus used in the study; Training procedure; How bees were tested.

Studies overnight memory retention of foraging skills in bumblebees. Increase in foraging effiency during the day; Characterization of overnight changes in the bees' preferences and foraging efficiency.