Importance of flies for Mangifera indica cv. Kent (Anacardiaceae) pollination and fruit set in the Sudano-Sahelian area of Cameroon

Abstract

Field experiments were conducted to find out the floral activity of insects on Mangifera indica cv. Kent (Anacardiaceae) for assessing the impact on pollination and fruit set in 2018/2019 and 2019/2020 seasons. Two treatments were made with open-pollinated flowers (treatment A) and secondly bagged panicles (treatment B). The diversity of the entomofauna and certain foraging parameters were recorded in treatment A and a comparison of fruit set was made for both treatments. Twenty-six insect species were recorded overall. Bees were sporadic with a relative abundance of only ˂ 9%. The order Diptera with a relative abundance of 89.35% was the most species-rich. Chrysomya putoria (Calliphoridae) and an undetermined species belonging to the genus Sarcophaga (Sarcophagidae) were constant species. These flies were active daily during study with a peak of activity at the 7:00-10:00 a.m. recorded time interval. Flower visits by flies were noted as 89% for nectar harvesting and 11% for pollen collection. During their foraging activity, flies induced the pollination of hermaphroditic flowers which resulting in an improvement in mango fruit yields. The rate of mature fruit per panicle was 0% in treatment B during both years, with 1.07% in 2018/2019 and 1.85% in 2019/2020 in treatment A. Flies are here identified as essential flower-visiting insects and pollinators of M. indica which guaranteed fruiting of this crop in Maroua (Cameroon).