Combined effects of Chalicodoma rufipes (Hymenoptera: Megachilidae) activity and compost on pollination and production of Phaseolus vulgaris pink variety (Fabaceae) at Dang (Ngaoundéré, Cameroon)

To evaluate synergistic effect of compost and Chalicodoma rufipes on Phaseolus vulgaris pink variety production, during the 2018 and 2021 cropping seasons, experiments were carried out in a complete randomized block design with three treatments: subplots applied with compost; subplots applied with NPK-fertilizer; subplots applied neither with compost, nor with NPK. Other four treatments were made up of 1220 labelled flowers comprising two differentiated according to the presence or absence of protection of flowers from insect visits; the third with flowers protected and uncovered when flowers were opened, to anable C. rufipes visit and the fourth with flowers uncovered and reprotected from insect or any other organism visits. Chalicodoma rufipes’s daily rhythm of activity, its foraging behavior on flowers and its pollination efficiency were evaluated. Results reveal that compost significantly increased (P < 0.001) P. vulgaris plants biomass. Among the 13 insect species recorded on P. vulgaris flowers, C. rufipes ranked second with 20.84% of the 782 visits. Chalicodoma rufipes intensely harvested nectar. The combined effet of C. rufipes and compost notably increased the fruiting rate, the number of seeds per pod and the percentage of normal seeds by 49.4%, 13.8% and 26.63%, respectively. Hence, application of compost and preservation of C. rufipes nests close to P. vulgaris fields is recommended to improve production of this important crop legume in the region.