Pollination efficiency of Apis mellifera (Hymenoptera : Apidae) on Cosmos sulphureus L. (Asteraceae) flower heads in Sarh (Moyen-Chari, Chad)

To determine the value of Cosmos sulphureus L. (Asteraceae) for beekeeping and to assess the impact of Apis mellifera (Hymenoptera: Apidae) on the achene yields of this Asteraceae species in Chad, the foraging and pollination activities of bees on C. sulphureus florets were observed in the Moyen-Chari Province.From September 2023 to October 2024, the experiments involved 540 flower heads divided into four treatment groups: two treatments distinguished by the presence or absence of protection for the florets against visits by A. mellifera and other insects ; a third group protected from insects, then uncovered and visited exclusively by A. mellifera before being protected again ; and a fourth group protected from insects, then uncovered and reprotected without any visits by insects or other organisms.This bee's foraging behavior on the florets, its pollination efficiency, the fruits et rate, and the percentage of normal achenes were evaluated.The results show that, among the 25 insect species recorded on the flower heads of C. sulphureus, A. mellifera ranks first accounting for 21.15% of the 4,066 visits and harvests nectar very intensively and pollen intensively.The average foraging speed is 20.83 florets per minute.Through its pollination Pollination efficiency… NINGATOLOUMClautin et al.