The Flower Colour Influences Spontaneous Nectaring in Butterflies: a Case Study with Twenty Subtropical Butterflies

Butterflies have a wide spectrum of colour vision, and changes in flower colour influence both the visiting and nectaring (the act of feeding on flower nectar) events of them. However, the spontaneous behavioural response of butterflies while foraging on real flowers is less characterised in wild conditions. Hence, this study intends to investigate flower colour affinity in wild butterflies in relation to nectaring frequency (NF) and nectaring duration (ND). Six distinct flower colours were used to study spontaneous nectaring behaviour in 20 species of subtropical butterflies. Both NF and ND greatly varied in the flower colours they offered. Yellow flowers were frequently imbibed by butterflies for longer durations, followed by orange, while red, pink, white and violet flowers were occasionally nectared in shorter bouts. Though butterflies have a general tendency to nectar on multiple flower colours, the Nymphalids were more biased towards nectaring on yellow flowers, but Papilionids preferred both yellow and orange, while the Pierids were likely to display an equal affinity for yellow, orange and violet flowers as their first order of preference. Even if the blooms are associated with higher nectar concentrations or a significant grade reward, the butterfly may prefer to visit different-coloured flowers instead. Flower colour choice appears to be a generalist phenomenon for butterflies, but their specialist visiting nature was also significant. Nymphalid representatives responded to a wider variety of floral colour affinities than Pierid and Papilionid species. The colour preference of butterflies aids in the identification of flowers during foraging and influences subsequent foraging decisions, which ultimately benefits pollination success. The current information will support the preservation and conservation of butterflies in their natural habitats.