Solanum scabrum Mill. (Solanaceae) is a traditional leafy vegetable of major nutritional and socioeconomic value in Sub-Saharan Africa. Although capable of autonomous self-pollination, the precise contribution of native anthophilous insects—particularly buzz-pollinating bees—remains insufficiently quantified in Afromontane agroecosystems. This study evaluated the floral visitor complex, foraging behavior of Amegillacalens (Hymenoptera: Apidae), and insect-mediated yield enhancement in Bambili (North-West Cameroon) across two consecutive cropping seasons (2024/2025 and 2025/2026). Four experimental pollination treatments were established: open pollination (Treatment 1/1′), autonomous self-pollination in bagged flowers (Treatment 2/2′), single visit by A. calens on bagged flowers (Treatment 3/3′), and bagged control without insect visits (Treatment 4/4′). Data were analyzed using Generalized Linear Mixed Models (GLMMs) and Linear Mixed Models (LMMs), accounting for nested spatial and individual plant random effects. Amegillacalens was the predominant visitor, accounting for over 70% of total visits in both years. By vibrating its thoracic muscles (buzz pollination), A. calens efficiently extracted pollen from poricidal anthers. Open pollination significantly increased the mean number of seeds per fruit (69.10 ± 14.56 vs. 54.03 ± 10.71 seeds; p < 0.001) and seed normality (98.44% vs. 75.86%; p < 0.001) compared to autonomous selfing. A single visit by A. calens significantly increased seed number per fruit (+4.43 seeds) and normal seed percentage (+11.15%) in both study cycles. However, its effect on fruit set and mean fruit weight exhibited inter-annual variation, showing significant gains in 2024/2025 but non-significant differences in 2025/2026 (p > 0.05). Solanum scabrum possesses a mixed-mating system where specialized buzz pollinators provide essential pollination services that optimize seed set and seed vigor. Conserving wild bee nesting sites and pollinator-friendly agricultural management are strongly recommended for regional smallholder farming systems.
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