Foraging and pollination behavior of Apis melliferaadansonii L. (Hymenoptera, Apidae) on Phaseolusvulgaris (Fabaceae) flowers at Maroua (Cameroon)

To evaluate the impact of Apis mellifera adansonii on pod and seed yields of Phaseolus vulgaris (red and small seeds), its foraging and pollinating behavior were studied in Maroua, during the June-August 2010 and 2011 cropping seasons. Treatments included unlimited floral access by all visitors, bagged flowers to avoid all visits, and limited visits of A. m. adansonii. Observations were made on 108 flowers per treatment of which all flower visitors were recorded. The bee seasonal rhythm of activity, its foraging behavior on flowers, and its pollination efficiency (fruiting rate, number of seeds/pod and percentage of normal seeds) were recorded. Twenty-four insect species visit P. vulgaris flowers. A. m. adansonii was the most frequent visitor and they intensely and exclusively foraged nectar. The foraging speed was 27.98 flowers/min. The foraging activity of A. m. adansonii resulted in a significant increase in fruiting rate by 61.25 and 49.38%, the number of seeds/pod by 28.54 and 9.66% and the normal seeds/pod by 8.18 and 7.25%, respectively in 2010 and 2011. Hence, conservation of A. m. adansonii hive close to P. vulgaris crop fields should be recommended to improve pod and seed production in the region.