Learning context modulates aversive taste strength in honey bees

Abstract

The capacity of honey bees (Apis mellifera) to detect bitter substances is controversial because they ingest without reluctance different kinds of bitter solutions in the laboratory, whereas free-flying bees avoid them in visual discrimination tasks. Here, we asked whether the gustatory perception of bees changes with the behavioral context so that tastes that are less effective as negative reinforcements in a given context become more effective in a different context. We trained bees to discriminate an odorant paired with 1 mol l −1 sucrose solution from another odorant paired with either distilled water, 3 mol l −1 NaCl or 60 mmol l −1 quinine. Training was either Pavlovian [olfactory conditioning of the proboscis extension reflex (PER) in harnessed bees], or mainly operant (olfactory conditioning of free-walking bees in a Y-maze). PER-trained and maze-trained bees were subsequently tested both in their original context and in the alternative context. Whereas PER-trained bees transferred their choice to the Y-maze situation, Y-maze-trained bees did not respond with a PER to odors when subsequently harnessed. In both conditioning protocols, NaCl and distilled water were the strongest and the weakest aversive reinforcement, respectively. A significant variation was found for quinine, which had an intermediate aversive effect in PER conditioning but a more powerful effect in the Y-maze, similar to that of NaCl. These results thus show that the aversive strength of quinine varies with the learning context, and reveal the plasticity of the bee's gustatory system. We discuss the experimental constraints of both learning contexts and focus on stress as a key modulator of taste in the honey bee. Further explorations of bee taste are proposed to understand the physiology of taste modulation in bees.

Visual acuity trade-offs and microhabitat driven adaptation of searching behaviour in psyllids (Hemiptera: Psylloidea: Aphalaridae)

“…The object detection threshold of different psyllid species was tested in a V-shaped maze, which was adapted from a conventional Y-shaped maze previously used to test free-flying insects (Giurfa et al, 1996(Giurfa et al, , 1997Reisenman and Giurfa, 2008) and, more recently, walking insects (Yilmaz et al, 2014;de Brito Sanchez et al, 2015). Experiments were conducted in a controlled laboratory chamber surrounded by white fabric curtains and illuminated from the top by four Philips Master TLSHE slimline 28W/865UV+ daylight fluorescent tubes (Philips, The Netherlands) with specially fitted highfrequency (1200 Hz) ATEC Jupiter EGF PMD2614-35 electronic dimmable ballasts.…”

Olfactory experience shapes the evaluation of odour similarity in ants: a behavioural and computational analysis

“…Studies in bees have shown that the shape of the generalization gradient obtained after differential conditioning (and in these cases, the magnitude of the peak shift) could vary according to some stimulus characteristics, such as the relative difference between the positive and the negative reinforcements or the relative frequency of CS+ and CS− trials [55,60]. This indicates that the width of excitatory and inhibitory gradients depends on these and probably other parameters [61]. For instance, in our case, a reinforcement more aversive than quinine or an increase of the number of CS− trials could have enlarged the width of the inhibitory generalization gradients, making them probably larger than the excitatory generalization gradients.…”

Como Treinar Sua Abelha: Métodos Aplicados À Biologia Cognitiva Da Polinização

“…Essas duas formas de condicionamento podem ser atingidas em dois tipos de abordagens: o condicionamento absoluto, no qual o animal é treinado com apenas um estímulo condicionado (EC+) seguido de recompensa (ENC); e o condicionamento diferencial, no qual o animal é apresentado a dois estímulos, um associado a uma recompensa (EC+) e um sem a recompensa ou com uma punição, como solução de quinina ou sal que são substâncias de sabor aversivo para as abelhas (EC-). A apresentação de punição ao animal pode melhorar o processo de discriminação entre estímulos, pois os custos de uma resposta errada são maiores (Sanchez et al 2015). Assim, no condicionamento diferencial, o animal deve associar um sinal à recompensa enquanto o outro sinal está associado a ausência de recompensa ou punição.…”

“…O EC-pode ser a ausência de solução de sacarose, ou ainda, substâncias aversivas para as abelhas. Recomenda-se solução concentrada de cloreto de sódio (NaCl) nesses casos (Sanchez et al 2015). A apresentação de EC às abelhas, no caso do condicionamento olfativo, pode ser feita de forma precisa, com aparelhos controlados por microcomputadores (Szyszka et al 2014), o que permite um melhor controle experimental.…”