Butterfly diversity and effect of temperature and humidity gradients on butterfly assemblages in a sub-tropical urban landscape

The butterfly assemblages of urban ecosystems of Delhi were studied for a period of one year to investigate their diversity. The objective of the study was to understand the dynamics of the butterfly assemblages with respect to changing temperature and humidity levels. We tested the hypothesis that the diversity of butterflies would differ significantly across sampling period owing to pronounced temperature and relative humidity differences throughout the year. The Pollard walk method was used for butterfly survey. Twelve months of intensive sampling at four study sites with 24 temporal replicates per site yielded 14,913 individuals belonging to 75 species. Butterfly community showed a biannual peak of species richness and abundance. The maximum diversity was recorded in the pre-monsoon period between the months of April and May unlike most other studies from India which have reported April-May as the months of lowest diversity. The lowest diversity was observed during winter. Previous studies have shown that tropical insect communities have higher diversity during high precipitation periods. In this study, we found an additional peak of diversity during the pre-monsoon in addition to the post-monsoon months. The study quantitatively assessed community assemblages between ecosystems across a temperature gradient evaluating potential conservation role of natural areas and parks in urban landscapes.