Vertical stratification of the butterfly flight and its variations with forest succession of a tropical forest in Sri Lanka

We assessed and compared the vertical stratification of butterfly flight in two forest types within the Maragamuwa forest regeneration study site (FRSS), Matale, Sri Lanka.Maragamuwa FRSS has two forest patches of different age categories, one is Early Secondary Forest (ESF) and the other is Late Secondary Forest (LSF).Butterfly flying heights recorded in both forest areas.The flight divided into three groups: Low level (0-1m), mid-level (1-3m), and high level (>3m).A negative correlation (r) between butterfly abundance and flying height was observed by performing the Pearson correlation analysis (ESF r=-0.677,LSF r=-0.766;p<0.05).In LSF, the highest species richness recorded at the mid-level (DMg = 9.94), which has a good understory, while the species richness was higher in the low level (DMg = 7.61) of the ESF, which has a good ground vegetation.The species richness was lowest at the high level in both forest types (ESF DMg =4.18, LSF DMg = 5.71).Butterflies of the family Papilionidae preferred to fly at high levels, and family Lycaenidae butterflies were more abundant at low levels, which proves a positive correlation between flying height and wingspan.Flying height increased with the wingspan (r = 0.576; p<0.05).The main findings of this study highlight the variation of the butterfly assemblage and flying heights with the forest succession and resource availability.