Floral preferences of bumblebees (Bombus edwardsii) in relation to intermittent versus continuous rewards (original) (raw)
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The influence of past experience with flower reward quality on social learning in bumblebees
Bombus terrestris decision making flower choice foraging innate colour bias social learning Foraging decisions can be influenced by innate biases, previous individual experience and social information acquired from conspecifics. We examined how these factors interact to affect flower colour preference in the large earth bumblebee, Bombus terrestris dalmatinus. Individual bees with no experience foraging on coloured flowers were first tested for innate colour biases on an unrewarded array of blue and yellow artificial flowers. Depending on treatment, bees then acquired individual experience foraging on a colour (either blue or yellow) associated with high-quality sucrose rewards, or a colour with low-quality sucrose rewards, or they did not acquire any individual experience. Bees were then exposed to the alternative colour associated with conspecific demonstrator bees (social information) or the alternative colour with no social information. Bees that had no individual experience visited flower colours that were associated with conspecific demonstrators (social information) but only significantly if the socially demonstrated colour was one for which bees had an innate bias. When bees had individual experience foraging on a colour with high-quality rewards they continued foraging on that colour, and generally did not visit the socially demonstrated alternative colour, regardless of innate colour bias. Alternatively, when bees had individual experience foraging on colours with low-quality rewards, they made more visits to the socially demonstrated alternative flower colour, but only when the alternative colour was the colour for which they had an innate bias. Bees that had no access to social information continued to forage on low-reward coloured flowers. Thus we show that reward quality of resources with which bees have individual experience affects the use of social information but with an important role of innate biases.
Effects of a reward downshift on the consummatory behavior and flower choices of bumblebee foragers
Physiology & Behavior, 2003
Insect foragers often exhibit flower constancy, the tendency to visit single flower types rather than sample alternative flowers that provide equal or higher levels of reward. We employed a negative incentive contrast procedure to examine whether a decrease of sucrose concentration in a regularly visited flower type affects bumblebee (Bombus impatiens) consummatory or choice behavior. Subjects were trained to enter a test arena where they foraged on a single, red, artificial flower that contained 140 ml of sucrose solution. Subjects were reinforced with a concentration of either 0.50 or 0.20 sucrose solution in 20 trials and in 12 subsequent test trials subjects were given a choice between a red and yellow flower that each contained 140 ml of 0.20 sucrose solution. Subjects that experienced a downshift of reward showed an abrupt disruption in consumption of sucrose solution from the red flower. These subjects were also significantly more likely to visit the novel yellow flower than subjects that were reinforced with 0.20 sucrose solution in red flowers in all trials. However, the effects of the downshift of reward were transient and appeared to disrupt consummatory behavior more strongly than flower preferences. These results support the idea that bumblebee foragers form expectations of reward in flowers-as is implied by the results of studies of honeybees-and suggest that unrealized expectations of reward may cause foragers to sample alternative flowers or to fly considerable distances in search of particular types of flowers. D
Interface focus, 2017
The question of when to collect new information and how to apply that information is central to much of behaviour. Theory suggests that the value of collecting information, or sampling, depends on environmental persistence and on the relative costs of making wrong decisions. However, empirical tests of how these variables interact are lacking. We tested whether bumblebee foraging decisions are indeed influenced by these two factors. We gave bees repeated choices between a resource providing a steady, mediocre reward and a resource fluctuating between a low reward and a high reward. In this paradigm, we manipulated environmental persistence by changing how long the quality of a fluctuating resource remained stable at one reward level. We manipulated the costs of decision errors by changing the relative values of the available rewards. Bees sampled the fluctuating resource more frequently when it changed quality more frequently, indicating that they measured environmental persistence ...
Multiple rewards have asymmetric effects on learning in bumblebees
Keywords: Bombus impatiens bumblebee learning memory multitasking nectar pollen pollination 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 o...
Foraging Response of Turkish Honey Bee Subspecies to Flower Color Choices and Reward Consistency
Journal of Insect Behavior, 2010
Honey bees (Apis mellifera anatolica) were subjected to sequential trials where they were given the choice between a featurepositive and a feature-negative feeding plate. The ʻfeatureʼ being manipulated is the presence of a single blue circle among three circles marking the location of a small sucrose reward. That is, a ʻfeature-negativeʼ target had three white circles, while a ʻfeature-positiveʼ target had two white circles and one blue one. Two experiments were performed. In both experiments, each bee was tested under two different reward scenarios (treatments). In the first experiment, during the feature-positive treatment bees received 4μl of 2moll -1 sucrose when choosing the feature-positive plate, but received 4μl of saturated NaCl solution (saltwater) when choosing the feature-negative plate. During the feature-negative treatment, bees were rewarded when visiting the featurenegative plate, while visitation to the feature-positive plate only offered bees the saltwater. The second experiment was a repeat of the first except that pure water was offered instead of saltwater in the non-rewarding feeding plate. As an experimental control, a set of bees was offered sequential trials where both the feature-positive and feature-negative plates offered the sucrose reward. Bee feeding plate choice differed between the feature-positive and feature-negative treatments in both experiments. Bees favored the feeding plate type with the sucrose reward in each treatment, and never consumed the saltwater or pure water when encountered in either treatment. Further, behavior of bees during both the feature-positive and feature-negative treatments differed from that of control bees. However, neither feature-positive nor feature-negative learning reached high levels of success. Further, a feature-positive effect was seen when pure water was offered; bees learned to solve the feature-positive problem more rapidly. When we tested bees using simply the choice of blue versus white targets, where one color held the sucrose reward and the other the saltwater, a beeʼs fidelity to the color offering the sucrose reward quickly reached very high levels.
Learning reward expectations in honeybees
Learning & Memory, 2007
The aim of this study was to test whether honeybees develop reward expectations. In our experiment, bees first learned to associate colors with a sugar reward in a setting closely resembling a natural foraging situation. We then evaluated whether and how the sequence of the animals' experiences with different reward magnitudes changed their later behavior in the absence of reinforcement
Animal Behaviour, 1999
We tested risk sensitivity towards variability in volume of reward with harnessed honeybees, Apis mellifera, in a proboscis-extension conditioning paradigm. We conditioned each subject to turn its head and extend its proboscis towards one of two presented odours; one odour was associated with a constant reward volume and the other with a variable reward volume that was either low or high, with probabilities P=0.75 and (1 P)=0.25, respectively. The volumes of rewards were varied among three experimental conditions. In conditions I and II, the variable reward option included a low reward of zero (i.e. reinforcement was withheld in the low reward value); in condition I, the mean of the variable and of the constant reward options were the same, and in condition II, the variable reward option had a higher mean reward than the constant reward option. The behaviour of subjects did not differ between treatments and the majority of individuals were risk averse. In condition III, the variable reward option did not include a zero reward and the mean reward did not differ between options. Very few of the individuals assigned to condition III developed a preference for either reward option. Thus, honeybees are risk sensitive to variability in volume of reward in some conditions and the degree of risk sensitivity depends on characteristics of the reward distributions. The most salient characteristic may be a relative measure of variability, such as the value of the coefficient of variation of reward. The experimental paradigm that we developed is a powerful tool for studying the mechanism of risk sensitivity in bees, as well as other aspects of learning, decision making, perception and memory.
Effects of Experience on Short- and Long-term Foraging Performance in Bumblebees
Ethology, 2010
Honeybees in natural settings show a gradual increase in foraging performance similar to the general pattern of lifetime performance seen in a wide variety of animals including humans. To quantify the factors contributing to such gradual increase in foraging success, we studied bumblebees foraging on pepper plants inside a greenhouse. This allowed us to combine the global measure of the net rate of food delivery to the hive with a detailed examination of bees' performance at flowers over time. Although bees exhibited short-term improvements in foraging ability during their first few foraging trips, we did not observe the predicted long-term increase in performance over days. Our results suggest that a variety of flower-handling tasks, flower choice and movements between plants can be learned quickly under the simple greenhouse settings. The long-term increase in performance under natural settings may be caused by factors including spatial orientation and locating the best plant species, flower patches and individual plants over a large area.
PLoS ONE, 2014
Background: Bumblebees use information provided inadvertently by conspecifics when deciding between different flower foraging options. Such social learning might be explained by relatively simple associative learning mechanism: the bee may learn to associate conspecifics with nectar or pollen reward through previous experience of foraging jointly. However, in some studies, observers were guided by choices of 'demonstrators' viewed through a screen, so no reward was given to the observers at the time of seeing other bees' flowers choice and no demonstrator bee was present at the moment of decision. This behaviour, referred to observational conditioning, implies an additional associative step as the positive value of conspecific is transferred to the associated flower. Here we explore the role of demonstrator movement, and the distance between observers and demonstrators that is required for observation conditioning to take place.