Age and attitude: How longevity influences cognitive biases in honeybee workers

This study examines how life expectancy influences cognitive biases in honeybee workers (Apis mellifera) and their emotional states affecting decision-making. Recent research indicates that emotions impact behaviour and cognition in various species, including invertebrates. We conducted three experiments to manipulate honeybee lifespan and assess its effects on judgement biases using a classic judgement bias paradigm. In the first experiment, we shortened the lifespan of bees through CO₂ anaesthesia or thoracic puncture. The second experiment involved feeding workers Nosema sp. spores to induce infection and evaluate its impact on survival and judgement. The final experiment focused on 'rebel workers', who have naturally longer life expectancies. We conditioned bees to associate specific odours with rewards and punishments, then measured their responses to ambiguous stimuli. Results showed that bees subjected to life-shortening treatments exhibited more optimistic cognitive biases, as indicated by an increased likelihood of extending their proboscis to ambiguous odours. Conversely, rebel workers with longer lifespans displayed more pessimistic biases, indicating a cautious foraging approach. Overall, our findings suggest that honeybee decision-making is closely tied to their longevity, with shorter-lived individuals adopting riskier strategies compared to their longer-lived counterparts.