Inhibitory learning of phototaxis by honeybees in a passive-avoidance task

Abstract

Honeybees are a standard model for the study of appetitive learning and memory. Yet, fewer attempts have been performed to characterize aversive learning and memory in this insect and uncover its molecular underpinnings. Here, we took advantage of the positive phototactic behavior of bees kept away from the hive in a dark environment and established a passive-avoidance task in which they had to suppress positive phototaxis. Bees placed in a two-compartment box learned to inhibit spontaneous attraction to a compartment illuminated with blue light by associating and entering into that chamber with shock delivery. Inhibitory learning resulted in an avoidance memory that could be retrieved 24 h after training and that was specific to the punished blue light. The memory was mainly operant but involved a Pavlovian component linking the blue light and the shock. Coupling conditioning with transcriptional analyses in key areas of the brain showed that inhibitory learning of phototaxis leads to an up-regulation of the dopaminergic receptor gene Amdop1 in the calyces of the mushroom bodies, consistently with the role of dopamine signaling in different forms of aversive learning in insects. Our results thus introduce new perspectives for uncovering further cellular and molecular underpinnings of aversive learning and memory in bees. Overall, they represent an important step toward comparative learning studies between the appetitive and the aversive frameworks.

Complexity and plasticity in honey bee phototactic behaviour

“…Absolute phototaxis towards UV seemed to be immune to aversive training, while the same behaviour towards blue was especially labile. Similar selective plasticity in the blue range was obtained by other studies using a comparable approach 26,27 . This could be linked to the relative efficiency of each wavelength in eliciting positive phototaxis, which was evident in our calibration data ( Fig.…”

The Neural Signature of Visual Learning Under Restrictive Virtual-Reality Conditions

“…Two reference genes were used for the normalization (see Table 1 ): Ef1a (E = 106%) and Actin (E = 110%) ( Marchal et al, 2019 ). Within-brain structure analyses showed that reference genes did not vary between learners and non-learners ( t test; all comparisons NS; see Supplementary Figure 3 ) thus enabling further comparisons between these two categories with respect to the three target IEGs.…”

“…Brains were collected 1 h after the retention test, which ensures that expression of all three genes was already induced (typically, from 15 to 90 min in the case of kakusei (Kiya et al, 2007;Ugajin et al, 2012) and 30-60 min in the case of Hr38 and Egr1 (Ugajin et al, 2018;Iino et al, 2020)). Two reference genes were used for the normalization (see Table 1): Ef1a (E = 106%) and Actin (E = 110%) (Marchal et al, 2019). Within-brain structure analyses showed that reference genes did not vary between learners and non-learners (t test; all comparisons NS; see Supplementary Figure 3) thus enabling further comparisons between these two categories with respect to the three target IEGs.…”

Conspecific and interspecific stimuli reduce initial performance in an aversive learning task in honey bees (Apis mellifera)

“…Future work should also consider using refined position and activity measurements such as the grid of infrared beams used by Kirkerud et al [40] and Nouvian and Galizia [81], or a computer vision approach similar to that used by Marchal et al [41] and Kimura et al [82] to precisely measure the pacing behavior observed in shuttle box experiments. Additionally, investigations on the habituation to social stimuli discussed in this paper could also consider the many principles of habituation and sensitization outlined by Thompson and Spencer [83], Groves and Thompson [84], and Rankin et al [85].…”

“…A growing body of research investigates aversive conditioning in a shuttle box, where unrestrained bees learn to alter their behavior to reduce shock or other aversive stimuli in a small runway. Research using this method has explored areas such as learning differences between drones and workers [38], learned helplessness [39], visual discrimination [40], modulation of phototaxis [41], detection of narcotics [42], and the roles of the dopamine, octopamine and the mushroom body in aversive learning [41,43,44].…”