Evaluation of the Foraging Activity and Pollination Efficiency of Apis mellifera L. (Hymenoptera: Apidae) on Urena lobata L. (Malvaceae) Flowers at Dang (Ngaoundere, Cameroon)

Field surveys of Urena lobata plant plots were conducted during two seasons in 2020 and 2021 aiming to determine the apicultural value of U. lobata and assess the pollination efficiency of Apis mellifera on fruiting rate and seed production. 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, uncovered, visited once by A. mellifera and rebagged; 100 flowers bagged then uncovered and rebagged without the visit of insects or any other organism. The foraging behavior of A. mellifera on flowers and its pollination efficiency were recorded. Results show that, among the flowering insects of U. lobata, A. mellifera was the main visitor and it intensely harvested nectar and slightly collected pollen. The highest mean number of honeybees per 1000 flowers was 132 and 209 in the morning between 8 am and 9 am during the flowering stage for the two studied period respectively in 2020 and 2021. The mean foraging speed was 8 flowers per minute in 2020 and in 2021. Via the pollination efficiency of one flower visit on U. lobata, A. mellifera has increased the fruiting rate by 10.46% and the percentage of normal seeds by 13.47%.