Diversity of flowering insects and effect of Apis mellifera (Hymenoptera: Apidae) on Anacardium occidentale (Anacardiaceae) L. 1975 Panicles in Garoua, North Cameroon

Abstract

In northern Cameroon, the diversity of pollinating insects and the specific role of the honeybee (Apis mellifera) in the fruit set of cashews (Anacardium occidentale) remain poorly studied, although pollination is an essential ecological service for agricultural productivity. To address this gap, we investigated pollinator diversity and the influence of honeybee foraging behaviour on cashew fruit set in Garoua across two flowering seasons (2022/2023 and 2023/2024. A total of 534 panicles were subjected to four treatment conditions based on insect access. Nineteen insect species were identified, with Hymenoptera Spp representing the most abundant group (73.63%). A. mellifera was consistently active, showing two daily foraging peaks between 8:00–9:00 a.m. and 2:00–3:00 p.m. Nectar collection dominated bee visits (65.42% in 2022/2023 and 80.54% in 2023/2024), while pollen gathering accounted for the remainder. Bee foraging effectively promoted pollination in perfect flowers, enhancing fruit set by 4.90% in 2022/2023 and 2.03% in 2023/2024. Additionally, the proportion of normal fruits increased by 84.43% and 58.06% respectively. These findings highlight the critical role of A. mellifera as a floral visitor and pollinator of A. occidentale, contributing significantly to cashew productivity in Garoua, Cameroon.