Pollinator-crop interactions are crucial for yield. Brown mustard is widely grown as an oilseed crop, yet declining pollinator populations can lead to pollination deficits and reduced yields. Although some studies have reported mustard flower visitors, details of plant-pollinator interactions and the effectiveness of bee management practices remain poorly understood. We aimed to uncover the dynamics of the flower resource, pollination ecology, and the potential for yield increases by stingless bees. We measured floral resources, conducted field surveys, and implemented five pollination treatments: open pollination, pollinator exclusion, and managed stingless bee treatments in open fields, netted fields, and greenhouse conditions. Mustard flowers opened throughout the daytime and peaked between 8.00 and 10.00 h. The availability of floral resources (nectar/spike and pollen/spike) remained higher from 8.00 to 12.00 h, and during this time, the abundance, richness, and diversity of flower visitors were also higher. Diverse insect groups pollinated mustard flowers, and effective native pollinators (based on the pollination service index values) were Apis cerana, Apis florea, Ceratina binghami, Lasioglossum cavernifrons, and Tetragonula pagdeni. Pollination modes remained diverse, as sternotribic, noto-sternotribic, and appendage-mediated. The installation of Indian stingless bees in mustard fields optimised yields, and the open field installation practice remained superior (seed yield: 1311.66 ± 88.12 kg/ha) to caged practices (netted fields: 856.23 ± 68.23 kg/ha and greenhouse fields: 901.86 ± 74.15 kg/ha). Based on these findings, it is suggested that farmers utilise supplementary stingless bees in mustard cultivation (via open field application) to enhance sustainable agricultural outputs.
Layek et al. (Tue,) studied this question.