IMPACT OF SEASONAL VARIATION ON SPECIES RICHNESS, DIVERSITY AND RELATIVE ABUNDANCE OF BUTTERFLIES IN BHILWARA DISTRICT, RAJASTHAN, INDIA

A study was conducted in Bhilwara district to assess seasonal variations in butterfly species richness, diversity and relative abundance from July 2022 to June 2025. A primary survey was conducted from July 2022 to June 2023 to identify sampling sites and transects, followed by monthly surveys from July 2023 to June 2025 to monitor seasonal changes in butterfly communities. A total of 49 species belonging to 37 genera, 13 subfamilies and five families of butterflies were observed in Bhilwara district. In terms of seasonal variation in butterfly communities, the highest number of butterfly species and individuals was noted during the rainy season (rainy 2025= 46 species; 1245 individuals and rainy 2024= 42 species; 1012 individuals) followed by winter season (winter 2023–24 = 39 species; 958 individuals and winter 2024–25 = 41 species; 886 individuals), and lowest number of butterfly species and individuals was noted during summer season (summer 2025= 36 species and 659 individuals and summer 2024= 37 species; 846 individuals). Values of different diversity indices, such as the Simpson diversity index (0.9646–0.9749), Shannon diversity index (3.476– 3.751), and Menhinick index (1.254–1.402) also varied with seasonal fluctuations. Species richness, diversity, population, and relative abundance of butterflies fluctuated due to variations in climatic conditions. Extremely high temperatures in summer season, as well as low temperatures during winter season and availability of adequate resources in these seasons, caused a decline in species richness and population, affecting adult and pupa survival. In contrast, the rainy season provided favorable host plant availability, offering higher species richness, diversity and abundance of butterflies. Furthermore, species vary in their tolerance to climatic changes, allowing some species to thrive in adverse environmental conditions. Occurrence of butterfly species also varies according to the season; some species appear throughout pyears, whereas others, such as Colotis vestalis, Hebomoia glaucippe and Suastus gremius, appear during specific seasons, such as the rainy season in the study area.