Foraging task specialization in honey bees (Apis mellifera): the contribution of floral rewards to the learning performance of pollen and nectar foragers.

Social insects live in communities where cooperative actions heavily rely on the individual cognitive abilities of their members. In the honey bee (Apis mellifera), the specialization in nectar or pollen collection is associated with variations in gustatory sensitivity, affecting both associative and non-associative learning. Gustatory sensitivity fluctuates as a function of changes in motivation for the specific floral resource throughout the foraging cycle, yet differences in learning between nectar and pollen foragers at the onset of food collection remain unexplored.

Honey bee colonies change their foraging decisions after in-hive experiences with unsuitable pollen.

Pollen is the protein resource for Apis mellifera and its selection affects colony development and productivity. Honey bee foragers mainly lose their capacity to digest pollen, so we expect that those pollen constituents that can only be evaluated after ingestion will not influence their initial foraging preferences at food sources. We predicted that pollen composition may be evaluated in a delayed manner within the nest, for example, through the effects that the pollen causes on the colony according to its suitability after being used by in-hive bees.

Changes in resource perception throughout the foraging visit contribute to task specialization in the honey bee Apis mellifera.

Division of labor is central to the ecological success of social insects. Among foragers of the honey bee, specialization for collecting nectar or pollen correlates with their sensitivity to sucrose. So far, differences in gustatory perception have been mostly studied in bees returning to the hive, but not during foraging.

In-hive learning of specific mimic odours as a tool to enhance honey bee foraging and pollination activities in pear and apple crops.

The areas devoted to agriculture that depend on pollinators have been sharply increased in the last decades with a concomitant growing global demand for pollination services. This forces to consider new strategies in pollinators' management to improve their efficiency. To promote a precision pollination towards a specific crop, we developed two simple synthetic odorant mixtures that honey bees generalized with their respective natural floral scents of the crop.

Differences in olfactory sensitivity and odor detection correlate with foraging task specialization in honeybees Apis mellifera.

Division of labor is central to the ecological success of social insects. Among honeybees foragers, specialization for collecting nectar or pollen correlates with their sensitivity to gustatory stimuli (e.g.

Young honeybees show learned preferences after experiencing adulterated pollen.

Pollen selection affects honeybee colony development and productivity. Considering that pollen is consumed by young in-hive bees, and not by foragers, we hypothesized that young bees learn pollen cues and adjust their preferences to the most suitable pollens. To assess whether young bees show preferences based on learning for highly or poorly suitable pollens, we measured consumption preferences for two pure monofloral pollens after the bees had experienced one of them adulterated with a deterrent (amygdalin or quinine) or a phagostimulant (linoleic acid).

Selective recruitment for pollen and nectar sources in honeybees.

Honeybees (Apis mellifera) use cues and signals to recruit nestmates to profitable food sources. Here, we investigated whether the type of resource advertised within the colony (i.e.

Pollen reinforces learning in honey bee pollen foragers but not in nectar foragers.

Searching for reward motivates and drives behaviour. In honey bees , specialized pollen foragers are attracted to and learn odours with pollen. However, the role of pollen as a reward remains poorly understood.

Learning of a Mimic Odor within Beehives Improves Pollination Service Efficiency in a Commercial Crop.

The growing global demand for pollination services leads producers to consider new strategies in pollinator management to improve its efficiency in agroecosystems [1-3]. Central place foragers, like honeybees, learn floral cues not only in the field but also inside the nest, where resource cues introduced into the hive improve foraging by guiding bees toward the learned stimuli [4]. In this regard, attempts to condition bees with crop-odor-scented food produced ambiguous results and lacked yield measurements [5-7].

Appetitive and aversive learning of plants odors inside different nest compartments by foraging leaf-cutting ants.

Cues inside the nest provide social insect foragers with information about resources currently exploited that may influence their decisions outside. Leaf-cutting ants harvest leaf fragments that are either further processed as substrate for their symbiotic fungus, or disposed of if unsuitable. We investigated whether Acromyrmex ambiguus foragers develop learned preferences for olfactory cues they experienced either in the fungus or in the waste chamber of the nest.

Avoidance of plants unsuitable for the symbiotic fungus in leaf-cutting ants: Learning can take place entirely at the colony dump.

Plants initially accepted by foraging leaf-cutting ants are later avoided if they prove unsuitable for their symbiotic fungus. Plant avoidance is mediated by the waste produced in the fungus garden soon after the incorporation of the unsuitable leaves, as foragers can learn plant odors and cues from the damaged fungus that are both present in the recently produced waste particles. We asked whether avoidance learning of plants unsuitable for the symbiotic fungus can take place entirely at the colony dump.

Odor Experiences during Preimaginal Stages Cause Behavioral and Neural Plasticity in Adult Honeybees.

In eusocial insects, experiences acquired during the development have long-term consequences on mature behavior. In the honeybee that suffers profound changes associated with metamorphosis, the effect of odor experiences at larval instars on the subsequent physiological and behavioral response is still unclear. To address the impact of preimaginal experiences on the adult honeybee, colonies containing larvae were fed scented food.

Learning through the waste: olfactory cues from the colony refuse influence plant preferences in foraging leaf-cutting ants.

Leaf-cutting ants learn to avoid plants initially harvested if they prove to be harmful for their symbiotic fungus once incorporated into the nest. At this point, waste particles removed from the fungus garden are likely to contain cues originating from both the unsuitable plant and the damaged fungus. We investigated whether leaf-cutting ant foragers learn to avoid unsuitable plants solely through the colony waste.

Effects of field-realistic doses of glyphosate on honeybee appetitive behaviour.

Glyphosate (GLY) is a broad-spectrum herbicide used for weed control. The sub-lethal impact of GLY on non-target organisms such as insect pollinators has not yet been evaluated. Apis mellifera is the main pollinator in agricultural environments and is a well-known model for behavioural research.

Behavioral and neural plasticity caused by early social experiences: the case of the honeybee.

Cognitive experiences during the early stages of life play an important role in shaping future behavior. Behavioral and neural long-term changes after early sensory and associative experiences have been recently reported in the honeybee. This invertebrate is an excellent model for assessing the role of precocious experiences on later behavior due to its extraordinarily tuned division of labor based on age polyethism.

Associative learning during early adulthood enhances later memory retention in honeybees.

Background: Cognitive experiences during the early stages of life play an important role in shaping the future behavior in mammals but also in insects, in which precocious learning can directly modify behaviors later in life depending on both the timing and the rearing environment. However, whether olfactory associative learning acquired early in the adult stage of insects affect memorizing of new learning events has not been studied yet.

Methodology: Groups of adult honeybee workers that experienced an odor paired with a sucrose solution 5 to 8 days or 9 to 12 days after emergence were previously exposed to (i) a rewarded experience through the offering of scented food, or (ii) a non-rewarded experience with a pure volatile compound in the rearing environment.

Volatile exposure within the honeybee hive and its effect on olfactory discrimination.

Honeybees of different ages and reproductive castes cohabit in the hive where they are exposed to many odors that might affect associative learning. Our aim was to analyze the role of odors pre-exposed as volatiles on appetitive learning in honeybees of different ages and search for their long-term effect both under natural and laboratory conditions. By evaluating memory acquisition and retention through a differential proboscis extension response conditioning, we found that hive-exposed odors offered as a reinforced conditioned stimulus during training promoted a learning-reduced effect [latent inhibition (LI)].

Age and rearing environment interact in the retention of early olfactory memories in honeybees.

Due to the changing behavioral contexts at which social insects are exposed during the adult lifespan, they are ideal models to analyze the effect of particular sensory stimuli during young adulthood on later behavior. Specifically, our goal is to understand early influences on later foraging behavior. For that, olfactory memories were established by worker honeybees to different pre-foraging ages using either (1) classical conditioning in the proboscis extension response (PER) paradigm or (2) the offering of scented-sugar solution under different rearing conditions.

Floral odor learning within the hive affects honeybees' foraging decisions.

Honeybees learn odor cues quickly and efficiently when visiting rewarding flowers. Memorization of these cues facilitates the localization and recognition of food sources during foraging flights. Bees can also use information gained inside the hive during social interactions with successful foragers.