Exploration of forest resource by both man and butterflies—a case study on utilization of medicinal plants as a larval resource by nymphalinae butterflies

India is renowned for its rich medico-cultural heritage. Despite modernisation coupled with scientific advancement, the rich traditional medicinal system cannot be overlooked. Interestingly, the chemical constituents of such medicinally significant plants also form the basis of host plant recognition by butterflies. Olfactory and gustatory cues and their associated chemosensory mechanisms of host plant identification at dual stages of their life cycle (i.e. larval feeding and oviposition) have been previously investigated.

Documentation of such therapeutically significant larval food plants of nymphalinae butterflies (Family: Nymphalidae) followed by recognition of their medicinal potential was undertaken across the Himalayan landscape of West Bengal, India. A specially designed questionnaire was prepared for these folklore therapists and traditional healers. The database was created for ascertaining the Informant Consensus Factor (ICF), Utilization Value (Uv) and Fidelity levels (F_L). Additionally, the Host Plant Specificity (H_PS) and Polyphagy Index (P_I) were determined to reflect the importance of such medicinal plant species as larval resource of butterflies. A total of 85 informants were interviewed, leading to the calculation of ICF, Uv and F_L for each plant species.

Thus, the therapeutic benefits of 28 plant species used against several categories of ailments were listed. The highest ICF value (1.000) was cited for diseases of the digestive system and disorders associated with the respiratory system. The maximum F_L of 100% was noted for Urtica dioica, Artemisia vulgaris, Dioscorea deltoides, Mimosa pudica and Hygrophila auriculata. Urtica dioica displayed the maximum Uv. Furthermore, Junonia lemonias, J. orithiya, Hypolimnas bolina and H. misippus possessed the highest H_PS. A maximum P_I value was determined for Junonia lemonias (5.477) followed by Hypolimnas bolina and H. missipus (5.000).

Thus, polyphagy is known to provide a stimulus among butterflies, enabling their sustenance through life history stages. Equally significant are such medicinal plants serving as botanical tools for traditional healers.