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Summary: A new study shows that bumblebees learn socially, and this resulted in a novel behavior becoming dominant across a group. These findings highlight the opportunity going forward to use social insects to address how simple cognitive mechanisms can underpin the development of complex behavioral phenomena. [ABSTRACT FROM AUTHOR]

Octopamine has broad roles within invertebrate nervous systems as a neurohormone, neurotransmitter, and neuromodulator. It orchestrates foraging behavior in many insect taxa via effects on feeding, gustatory responsiveness, and appetitive learning. Knowledge of how this biogenic amine regulates bee physiology and behavior is based largely on study of a single species, the honey bee, Apis mellifera. Until recently, its role in the foraging ecology and social organization of diverse bee taxa had been unexplored. Bumble bees (Bombus spp.) are a model for research into the neural basis of foraging and learning, but whether octopamine similarly affects sensory and cognitive performance in this genus is not known. To address this gap, we explored the effects of octopamine on gustatory responsiveness and associative learning in Bombus impatiens via conditioning of the proboscis extension reflex (PER) using a visual (color) cue. We found that octopamine had similar effects on bumble bee behavior as previously reported in honey bees; however, higher doses were required to induce these effects. At this higher dose, octopamine lowered bees’ gustatory responsiveness and appeared to enhance associative learning performance during the early phase of our experiment. Adding to recent studies on stingless bees (Meliponini), these findings support the idea that octopamine’s role in reward perception and processing is broadly conserved across Apidae, while pointing towards some differences across systems worth exploring further. [ABSTRACT FROM AUTHOR]

Animals develop food preferences based on taste, nutritional quality and to avoid environmental toxins. Yet, measuring preferences in an experimental setting can be challenging since ecologically realistic assays can be time consuming, while simplified assays may not capture natural sampling behavior. Field realism is a particular challenge when studying behavioral responses to environmental toxins in lab-based assays, given that toxins can themselves impact sampling behavior, masking our ability to detect preferences. We address these challenges by comparing different experimental methods for measuring sucrose concentration preference in bumble bees (Bombus impatiens), evaluating the utility of two preference chamber-based methods (ad libitum versus a novel restricted-sampling assay) in replicating bees' preferences when they fly freely between artificial flowers in a foraging arena. We find that the restricted-sampling method matched a free-flying scenario more closely than the ad libitum protocol, and we advocate for expanded use of this approach, given its ease of implementation. We then performed a second experiment using the new protocol to ask whether consuming the neonicotinoid pesticide imidacloprid, known to suppress feeding motivation, interfered with the expression of sucrose preferences. After consuming imidacloprid, bees were less likely to choose the higher-quality sucrose even as they gained experience with both options. Thus, we provide evidence that pesticides interfere with bees' ability to discriminate between floral rewards that differ in value. This work highlights a simple protocol for assessing realistic foraging preferences in bees and provides an efficient way for researchers to measure the impacts of anthropogenic factors on preference expression. [ABSTRACT FROM AUTHOR]