Reward and non-reward learning of flower colours in the butterfly Byasa alcinous (Lepidoptera: Papilionidae).

Learning plays an important role in food acquisition for a wide range of insects. To increase their foraging efficiency, flower-visiting insects may learn to associate floral cues with the presence (so-called reward learning) or the absence (so-called non-reward learning) of a reward. Reward learning whilst foraging for flowers has been demonstrated in many insect taxa, whilst non-reward learning in flower-visiting insects has been demonstrated only in honeybees, bumblebees and hawkmoths. This study examined both reward and non-reward learning abilities in the butterfly Byasa alcinous whilst foraging among artificial flowers of different colours. This butterfly showed both types of learning, although butterflies of both sexes learned faster via reward learning. In addition, females learned via reward learning faster than males. To the best of our knowledge, these are the first empirical data on the learning speed of both reward and non-reward learning in insects. We discuss the adaptive significance of a lower learning speed for non-reward learning when foraging on flowers.