Pollination Efficiency of Amegilla calens (Hymenoptera: Apidae) on Gossypium hirsutum L. (Malvaceae) Variety L457 Flowers at Meskine (Maroua, Cameroon)

This study was carried out to evaluate the impact of Amegilla calens bee on fruit and seed yields of G. hirsutum in an experimental field, in September 2018 and 2019. The experiments were carried out on 540 flowers divided in four treatments: 120 flowers accessible to all visitors; 120 flowers bagged to avoid all visits; 200 flowers protected and uncovered when they were opened, to allow A. calens visits; 100 flowers bagged then uncovered and rebagged without the visit of insects or any other organism. Bee’s daily rhythm of activity, its foraging behaviour on flowers, its pollination efficiency, the fruiting rate, the number of seeds per fruit and the percentage of normal seeds were evaluated. Among the 20 insect species recorded on G. hirsutum flowers, A. calens was the most frequent insect with 30.72 % of 655 visits. On flowers, individual bee intensely collected pollen and slightly harvested nectar. The mean duration of a visit per flower was 23.56 sec for pollen harvest and 13.68 sec for nectar collection. For the two years, through its pollination efficiency, A. calens increased the fruiting rate by 20.30 %, as well as the percentage of normal seeds by 32.39 %.