Hoist the colours: silviculture impacts fruit-feeding butterfly assemblage colouration in the Atlantic Forest

Abstract

Organismal colours have long captivated and inspired naturalists and scientists. Since colours depend on the life history of a species, it is expected that they respond to environmental changes, especially in an increasingly anthropized world. Aiming to evaluate how this trait responds to different anthropogenic disturbances, we assess wing colour aspects of fruit-feeding butterflies sampled in Atlantic Forest remnants. These remnants, with well-defined understory and canopy, are crossed by artificial edges and surround exotic pine silviculture areas of different ages, representing landscapes commonly found in the subtropical Atlantic Forest. We obtained colour measurements of brightness, saturation, contrast, colour diversity and heterogeneity, and the presence of eyespots and iridescence for dorsal and ventral wing surfaces of 47 fruit-feeding butterfly species. We evaluated colour trait distribution and abundance in the distinct native (understory and canopy) and anthropized (edge, old and young Pinus) habitats, and hypothesised that butterfly assemblage colouration will differ in each habitat due to biotic and abiotic differences. In addition, butterfly assemblages in anthropized environments should present less diverse colour traits due to the pressures generated by anthropogenic actions, like microclimate changes and higher exposure to predation. As expected, the natural environments have butterflies with diverse colours and unique contrast colour traits. These patterns are not found in anthropized ones despite artificial edges presenting brighter and even more diverse colours. However, pine silviculture areas present butterflies with less diverse colours, leading the most colourful species to disappear. We demonstrate that different anthropogenic disturbances can impact butterfly colouration. Our results reinforce the close relationship between butterfly colouration and the environment, highlighting that colours can be used as bioindicators for conservation purposes, representing a useful form of functional biodiversity.