Interactions of flower visitors with bitter gourd (Momordica charantia L.) and effects of right target and wrong target flower visits on plant reproduction

Studying flower visitors, visitation patterns, and pollinator effectiveness can provide valuable insights into the interactions between plants and pollinators. Bitter gourd (Momordica charantia), a key vegetable crop, relies on flower visitors, especially pollinators. However, the specific role of wild pollinators and the impact of different visit types on bitter gourd pollination remain unclear. We aimed to uncover plant-pollinator interactions on the crop species. We recorded the flower visitors and their visitation patterns, categorising visits as right target when the visitor collected floral resources, and as wrong target when the visitor did not collect any resources from the flowers. We also determined the impacts of two types of flower visits on plant reproduction based on pollen deposition and the resulting fruit and seed sets after a single visit by different pollinators. Several insect species visited bitter gourd flowers, while the most abundant and effective pollinators (based on the pollination service index, PSi) were Apis cerana, Apis dorsata, Apis florea, Austronomia ustula, Lasioglossum albescens, Lasioglossum cavernifrons, Lasioglossum funebre, and Nomia (Hoplonomia) elliotii. Most visitors, especially bees, made both the right target and the wrong target visits to female flowers. In addition to the right target visits, pollinators deposited significant pollen grains on flower stigmas via wrong target visits, leading to fruit and seed sets. These findings highlight the overlooked yet crucial role of wrong target visits in pollination and reproductive success.