Floral visitor assemblages in medicinal Lamiaceae and nectar sugar dynamics of Ocimum sanctum in the North Western Himalayan region

Lamiaceae family is economically important due to its aromatic, medicinal and industrial uses. This study investigated seven species viz. Lavendula officinalis, Mentha piperita, Ocimum sanctum, O. basillicum, Salvia rosmarinus, Thymus vulgaris, Thymus serphyllum to document the insect floral visitors, their foraging behaviour and their role of pollination in O. sanctum L. A total of 23 insect species were recorded, with Hymenoptera comprising the dominant group (85.6%). O. sanctum had the highest frequency of insect visits, followed by Salvia officinalis and O. basilicum primarily by Apis mellifera, A. cerana, and solitary bees. With an average amount of 0.38 ± 0.05 µl per flower and a sugar concentration ranging from 8.5% to 12.7%, nectar production in O. sanctum peaked between 0900 and 1100 h. Pollination studies revealed markedly higher seed yield under open pollination (24.95 ± 0.42 g/plant) and bee-pollination (24.19 ± 0.15 g/plant) compared with pollinator-exclusion (1.05 ± 0.09 g/plant). Test weight (36–37 mg) and seed germination (up to 68.26 ± 0.59%) were also significantly enhanced under insect-mediated pollination.The study shows a species level variation in insect visitors in each plant species and also underscore the ecological significance of insect pollinators to maintain their reproduction activities in medicinal Lamiaceae crops.