Impact of Amegilla calens and Apis mellifera Pollination on Gossypium hirsutum var. QR1302 Flowers at Tchabbal-Mounguel (Ngaoundéré, Cameroon)

The investigations were carried out from September 10 through October 13, 2017 at Tchabbal-Mounguel. On Gossypium hirsutum flowers, investigations were done on many aspects of the pollination services of Amegilla calens and Apis mellifera. G. hirsutum flowers were observed to study the activity of A. calens and A. mellifera and to evaluate their impacts on fruits and seed yields of this Malvaceae. The treatments consisted of 120 flowers left for free pollination, 120 flowers protected from insects using gauze bag nets, 200 protected flowers and visited exclusively by A. calens and A. mellifera and 100 protected flowers then opened and closed without any visit of insects or any other organisms. The results show that on cotton flowers, foragers of A. calens and A. mellifera highly collect nectar and pollen on its flowers. The highest mean number of individuals simultaneously active per 1000 flowers is 587 for A. calens and 526 for A. mellifera. Through their pollinating efficiency, A. calens and A. mellifera caused a significant increase in the fruiting rate by 7.00% and 17.33%, the number of seeds per fruit by 44.20% and 18.32% and the normal seeds by 47.78% and 5.66% respectively. Therefore, the conservation of the nests of A. calens and colonies of A. mellifera around G. hirsutum plantations are to be recommended to improve the fruit and seed yields of this Malvaceae.