Abundance and distribution of butterflies within a particular habitat signify floral diversity and, in turn, habitat quality. The generalized pattern of lepidopteran host plant consortium is the occurrence of host plant specialization along with a propensity of clades to remain associated with either the genus or family of host plants. The diversity of nectar plants they visit contributes towards the establishment of an elaborate plant–butterfly community. The present study was designed to explore the presence of pierid butterflies across 11 altitudinal gradients (≤ 300 masl; 301- 600masl; 601- 900 masl; 901-1200 masl; 1201-1500 masl; 1501-1800masl; 1801-2100 masl; 2101-2400 masl; 2401-2700 masl; 2701-3000 masl; ≥3001masl) in the Eastern Himalayan landscape of West Bengal, India. Identification of larval plant species followed by the determination of host plant specificity, diet breadth, and polyphagy index was undertaken. Adult nectaring resources were documented, and the information content of flower–butterfly interactions was quantified using the Shannon–Wiener Function and the Brillouin Index. The maximum number of individuals was recorded from ≤ 300 masl (791) while the minimum number of individuals was observed at ≥3001masl (137). The species diversity curve showed an increasing trend from lowest elevation, reaching its peak at 601–900 masl (4.99) and then declined at ≥3001masl (3.33). The highest species richness was noted at 601–900 masl (4.846) compared to the lowest value at 2401–2700 masl (1.92). A total of 56 plant species served as larval food resources for the butterflies, with 38.09% feeding from a single plant family and 35.71% from a single genus of food plant. Pierinae possessed higher diet breadth (0.435) as compared to Coliadinae (0.231). Eurema hecabe was most polyphagous (PI=4.243), while 7.14% of the species were monophagous. Seventeen plant species constituted the nectar resource of the butterflies. Higher values of information content as indicated by the Shannon–Wiener Function and Brillouin Index for Tabernæmontana coronaria (H'=5.537 Ĥ=5.267) and Fragaria nubicola (H'=5.247 Ĥ=5.011) indicated their greater preference among butterflies.