Pollination efficiency of Apis mellifera (Hymenoptera: Apidae) on Annona senegalensis (Annonaceae) flowers at Dang (Ngaoundere, Cameroon)

To evaluate the apicultural value of Annona senegalensis and the impact of Apis mellifera on fruit and seed yields of this Annonaceae at Dang, its foraging and pollinating activities were studied, from March to June in 2017 and 2020. Observations were carried out on 540 flowers divided in four treatments: 120 flowers accessible to all insects; 120 flowers bagged to avoid all visits; 200 flowers protected then uncovered during anthesis, to allow only Ap. mellifera visits; 100 flowers bagged then uncovered and rebagged without the visit of insects or any other organism. Workers daily rhythm of activity, their foraging behavior on flowers and their pollination efficiency were evaluated. Results showed that, honeybee foraged on An. senegalensis flowers throughout its whole blooming period. This bee intensely and exclusively harvested pollen. The greatest number of workers foraging simultaneously was 3 per flower and 340 per 1000 flowers. The mean foraging speed for each studied year was 3 flowers/min. Through its pollination efficiency on An. senegalensis, Ap. mellifera increased the fruiting rate by 26.19%, the mean number of seeds per fruit by 16.33% and the percentage of normal seeds by 22.41%. Hence, the installation of Ap. mellifera hive close to An. senegalensis plantations is recommended for increase beebread production as a hive product, and to improve fruit and seed yields of this plant.