Associative color learning and age in Heliconius butterflies

Emily Hollenbeck

Abstract

Flower color is an important attractant and many pollinators show distinct color preferences. This study determines if color preference and its lability differ between experienced and naïve Heliconius butterflies. Butterflies were offered nectar in Lantana camara inflorescences, which naturally have flowers of two colors (yellow and red) on a single inflorescence. Butterflies visited yellow flowers more frequently, with 76% of visits to yellow flowers when both flower colors offered nectar. When nectar was offered only by red flowers, yellow preference decreased significantly over time. Newly enclosed butterflies, offered inflorescences where only red flowers rewarded, showed a 56% yellow visitation rate over two days, 22% less than for butterflies previously offered inflorescences where both flowers were rewarded. These results suggest that yellow preference in Heliconius is both strong and innate, but can be weakened by experience. Further, it appears that naïve butterflies are more labile, allowing them to track changes in rewards more quickly. This reward-associated learning may help optimize foraging success by enabling individuals to adapt behaviorally to different environments.