Seasonal Variability and Ecological Distribution of Butterfly Populations in the Sub–Humid Ecosystems of Western West Bengal, India
Setwasri Kundu
Post Graduate Department of Zoology, Vidyasagar College, Salt Lake Campus, C L Block, Kolkata – 700091, India.
Sagata Mondal *
Post Graduate Department of Zoology, Vidyasagar College, Salt Lake Campus, C L Block, Kolkata – 700091, India.
*Author to whom correspondence should be addressed.
Abstract
Butterflies act as sensitive ecological indicators for evaluating habitat quality, seasonal dynamics and biodiversity patterns. The present study evaluated seasonal variability and ecological distribution of butterfly populations in Salanpur Block under Asansol Sadar Subdivision, Paschim Bardhaman District, West Bengal, India. Field surveys were conducted from March 2025 to April 2026 across seven representative sampling sites covering rural, semi-urban, wetland, agricultural, scrubland and industrially influenced habitats. Photographic documentation and occasional capture-and-release using a butterfly net were used for species identification. No specimens were collected during the study. Butterflies were recorded using Pollard Walk transects and visual encounter surveys during favourable weather conditions. A total of 4,272 individuals representing 101 species, 72 genera and six families were documented during the study period. Nymphalidae was the most species-rich and abundant family, with 34 species and 1,307 individuals, followed by Pieridae with 15 species and 1,194 individuals, Lycaenidae with 22 species and 956 individuals, Papilionidae comprised 11 species with 522 individuals, Hesperiidae with 18 species and 291 individuals, and Riodinidae with one species and two individuals. Commonly recorded species included Eurema hecabe, Catopsilia pyranthe, Pieris canidia, Graphium doson, Danaus chrysippus and Pseudozizeeria maha. Butterfly abundance showed seasonal fluctuations during the study period, with the highest monthly abundance recorded in August 2025 and the lowest in January 2026. Seasonal abundance peaked in the monsoon period, followed by the post-monsoon season compared with the winter and late summer periods, consistent with tropical butterfly dynamics in India. Regression analysis revealed a positive but non-significant correlation between butterfly abundance and temperature (p = 0.110), while relative humidity (p = 0.008) and rainfall (p = 0.000382) showed significant positive correlations. The findings provide baseline information on butterfly diversity and seasonal population patterns in the sub-humid ecosystems of western West Bengal.
Keywords: Seasonal abundance, butterfly diversity, Lepidoptera, habitat heterogeneity, climatic variables, rainfall, relative humidity, Salanpur Block, Paschim Bardhaman, sub-humid ecosystem