author(s)
Zra Ganava Venceslas, Mazi Sanda and Tchuenguem Fohouo Fernand-Nestor

abstract
To evaluate the impact of Dactylurina staudingeri on fruit and seed yields of Psorospermum febrifugum, its foraging and pollinating activities were studied in Ngaoundéré, from March 1^st to 8^th, in 2016 and 2017. The experiments were carried out on 540 flowers divided in four treatments: two treatments differentiated according to whether flower buds were protected or not against insect visits; two other treatments made up of flowers that were protected then exclusively exposed to D. staudingeri, or unbagged and reprotected without insect or any other organism visit. Stingless bee seasonal rhythm of activity, its foraging behavior on flowers, its pollination efficiency, the fruiting rate, the number of seeds per fruit and the percentage of normal seeds were evaluated. Results show that, D. staudingeri foraged on P. febrifugum flowers throughout its whole blooming period. Among the 37 insect species recorded on P. febrifugum flowers, D. staudingeri was the most frequent insect with 17.95% of 2373 visits. On flowers, individual bee intensely harvested nectar and slightly collected pollen. The mean foraging speed was 5.03 flowers / min. For the two years, through its pollination efficiency, D. staudingeri provoked a significant increment of the fruiting rate by 66.02%, as well as the percentage of normal seeds by 29.97%. Conservation of D. staudingeri nests close to P. febrifugum populations is recommended to improve fruit production, seed quality and stingless bee honey yield in the region.