Pollination ecology of butterflies in tropical plants of Western Ghats of India

Pollinators' visits to flowers are guided by various factors, with nectar availability being one of them. Butterflies remain underexplored with respect to their contribution to pollination. Extensive field observations were conducted to gain insights into the floral morphology of 23 plant species from the northern Western Ghats (a globally recognized and threatened biodiversity hotspot), which are frequently visited by butterflies. Plants were observed during their peak flowering season. Parameters such as the pollen shape, apertural characters, and exine ornamentation were studied. In total, 91 butterfly species foraging on the 23 plant species were encountered. The Nymphalidae family, with 28 species, was the most abundant, followed by members of Lycaenidae (22), Hesperiidae (20), Papilionidae (11), and Pieridae (10). Plain tiger butterfly (Danus chryssipus) was recorded visiting eight different plant species, the highest amongst all the butterfly species. The highest average nectar quantity was recorded in Psydrax dicoccos (1.27 μl/flower). The maximum number of butterfly visitors (56 different species) were observed to be foraging on Ligustrum robustum subsp. perrottetii, which is an endemic tree species, followed by Mappia nimmoniana, which attracted 44 butterfly species. Butterflies were captured using swipe nets, and their bodies were screened for any pollen load. Pollens of an isopolar nature were predominant, while 12 species exhibited a monad dispersal unit. Triaperturate pollens was the most common type with a tricolpate aperture condition. The present study highlights the possible role of butterflies as contributors to pollination.