Associative visual learning by tethered bees in a controlled visual environment

Abstract

Free-flying honeybees exhibit remarkable cognitive capacities but the neural underpinnings of these capacities cannot be studied in flying insects. Conversely, immobilized bees are accessible to neurobiological investigation but display poor visual learning. To overcome this limitation, we aimed at establishing a controlled visual environment in which tethered bees walking on a spherical treadmill learn to discriminate visual stimuli video projected in front of them. Freely flying bees trained to walk into a miniature Y-maze displaying these stimuli in a dark environment learned the visual discrimination efficiently when one of them (CS+) was paired with sucrose and the other with quinine solution (CS−). Adapting this discrimination to the treadmill paradigm with a tethered, walking bee was successful as bees exhibited robust discrimination and preferred the CS+ to the CS− after training. As learning was better in the maze, movement freedom, active vision and behavioral context might be important for visual learning. The nature of the punishment associated with the CS− also affects learning as quinine and distilled water enhanced the proportion of learners. Thus, visual learning is amenable to a controlled environment in which tethered bees learn visual stimuli, a result that is important for future neurobiological studies in virtual reality.

Higher-order discrimination learning by honey bees in a virtual environment

“…GABA immunoreactive feedback neurons (also termed protocerebral-calycal neurons or PCT neurons) are a major component of the honeybee mushroom body 41 . They exhibit learning-related plasticity 42 The success of bees in our VR setup shows that this environment is suitable for studying elemental [33][34][35] and non-elemental learning under controlled laboratory conditions. It has the advantage of reproducing these learning forms, which are typically exhibited by free-flying bees, in tethered bees walking stationary on a fixed point of space.…”

“…If the bee did not center the stimulus, the trial was ended after 30 s. No reinforcement was delivered in this case. This situation was infrequent due to phototaxis 33 . In average, a trial lasted 20 ± 3 seconds (mean ± S.E.…”

“…The use of virtual reality (VR) offers new possibilities to fill both voids. Recently, we established a VR environment in which bees walking stationary on a treadmill learn simple visual discriminations (differential conditioning: A+ vs. B-) of visual targets projected on a semicircular screen placed in front of them [33][34] . Experiments are performed under closed-loop conditions 34 so that the images perceived by the bee are constantly updated by its movements, thus creating a sensation of immersion within this virtual environment.…”

“…Experiments are performed under closed-loop conditions 34 so that the images perceived by the bee are constantly updated by its movements, thus creating a sensation of immersion within this virtual environment. Although VR allows learning simple associations [33][34][35] , it might affect negatively the solving of non-linear problems because of the constraints it imposes on active vision 34 .…”

Higher‐order discrimination learning by honeybees in a virtual environment

“…The use of virtual reality (VR) offers new possibilities to fill these voids. Recently, we established a VR environment in which a tethered bee walking stationary on a spherical treadmill learns simple visual discriminations (differential conditioning: A+ vs. B−) (Buatois, Flumian, Schultheiss, Avarguès‐Weber, & Giurfa, ; Buatois et al, ). To this end, visual targets to be discriminated are projected on a semicircular screen placed in front of the bee and the experimental situation is set under closed‐loop conditions, so that the images perceived by the walking bee are constantly updated by its movements, thus creating a sensation of immersion within this virtual environment.…”