Foraging experience modulates response to aversive odour cues in social wasps

Abstract

Experience can modify how animals respond to relevant stimuli from their environment, for example, through associative learning. In particular, odour stimuli play a central role in foraging by influencing decision making. Numerous studies have shown that odours can acquire relevance for an animal by becoming associated with food after appetitive experience. Therefore, studying to what extent learning can modulate the behavioural response to olfactory stimuli is essential to improve our understanding about the role of experience in food exploitation in nature. Here, we evaluated whether foraging experience can modulate the response of Vespula germanica, a food generalist and opportunistic eusocial wasp, towards an aversive odour. Through field experiments, we evaluated the response of naïve and experienced wasps towards an aversive odour under different scenarios, to also examine how these changes affect foraging decisions. Both naïve wasps and wasps that had foraging experience in the absence of the aversive odour were not attracted to the odour alone and avoided meat sources paired with this cue. However, wasps that had foraging experience with the aversive odour showed an opposite behavioural pattern; they preferred meat sources with the aversive odour and were equally attracted to this odour and the meat source. The behavioural repertoire (i.e. approaches, landings and search behaviour) elicited by the aversive odour after experience with it indicates that change in the response was due to associative learning, leading the odour which was initially repellent, to become attractive. Interestingly, the change in the aversive odour's valence occurred after one collecting experience and three to five visits promoted long-term memory of the odour. In conclusion, our results show that spontaneous responses to odours can be modulated by experience and provide new insights about learning and memory abilities of social wasps in relation to olfactory cues.