Flexible visual learning and memory in nectar foraging hornets

Pollinators, such as bees, develop flexible memories of colours, patterns and shapes, for efficient flower recognition. Here we tested whether other insects facing the same foraging problem have evolved similar cognitive abilities for flexible learning. We trained wild hornets from two species commonly found in Europe ( Vespa velutina nigrithorax and Vespa crabro ) to associate sucrose solution rewards to colour stimuli in a Y maze. Hornets of both species succeeded in differential and reversal learning, and developed short and long-term memories of the learnt associations. Thus, just like bees, hornet foragers can learn various visual cue-reward associations and remember them over several hours or days for selecting flowers. Our study in non-model species illustrates how standard conditioning approaches can be used to explore and compare the cognitive abilities of animals with similar foraging ecology.