Objective: Foraging and pollination activity of flowers of Gossypium hirsutum (Malvaceae) by Apis mellifera Linné (Hymenoptera: Apidae) have been observed in Garoua (North Cameroon), to determine the impact of worker bees on fruit and seed yields of this plant species. Methodology and results: From June to November 2010 and 2011, for each year, 200 flowers were labeled and divided in to two treatments, differentiated according to the presence or absence of protection against insect's activities. The foraging behavior on flowers, the fructification rate, the number of seeds per pod and the normal seeds rate were evaluated. Results show that A. mellifera foraged on G. hirsutum flowers from 6 am to 17 pm and throughout the whole blooming period. Through its pollination efficiency, A. mellifera increased significant fructification rate in the order of 20.55 %, the number of seed yields per pod was 26.21 % and the percentage of the normal seeds was 25.01 %. Conclusion and application of results: The installation of A. mellifera colonies close to G. hirsutum field could be recommended to improve its pods and seeds production.

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Most plant species require pollen transfer to produce fruits and set seeds. Although some insects visit flowers for nectar or pollen, not all flowering insects bring about pollination. To evaluate the impact of Apis mellifera Linnaeus on fruit and seed yields of Solanum nigrum Linnaeus, foraging and pollinating activities of worker bees were studied at Meskine in January 2019 and February 2020. The experiments were carried out on 540 flowers divided in four treatments: two treatments differentiated according to the presence or absence of protection of flowers regarding A. mellifera and other insect visits; the third with flowers protected and uncovered when they were opened, to allow A. mellifera visits and the fourth with flowers protected then uncorvered and reprotected without the visit of insects or any other organism. The foraging behaviour of A. mellifera on flowers, its efficiency pollination, the fruiting rate, the number of seeds per fruit and the percentage of normal seeds were evaluated. Results indicate that among 27 insect species recorded on flowers, A. mellifera ranked first accounting for for 34.16% of 2652 visits. This worker bee intensely harvested nectar and pollen. The mean foraging speed was 10.39 flowers / min. The mean abundance per 1000 flowers was 519.46. For the two years, throughout its pollination efficiency, A. mellifera increased the fruiting rate by 16.29%, as well as the percentage of normal seeds by 15.57%. Hence, the installation of honeybee colonies close to S. nigrum fields is recommended to improve fruit yields, seed quality, pollen as a hive product and honey production.