Pollination efficiency of Apis mellifera adansonii Latreille (Hymenoptera: Apidae) on Croton macrostachyus (Euphorbiaceae) flowers at Dang, Ngaoundéré, Cameroon
By: Népidé Ndobadé Carine, Tchuenguem Fohouo Fernand-Nestor
Key Words: Apis mellifera adansonii, Croton macrostachyus, Flowers, Pollination, Yield
Int. J. Biosci. 9(3), 75-88, September 2016.
To evaluate the impact of Apis mellifera adansonii on fruit and seed yields of Croton macrostachyus, the foraging and pollinating activities of worker bees were studied in Ngaoundéré. From May to June in 2013 and 2014, the experiments were carried out on 375 inflorescences divided in three treatments: two treatments differentiated according to the presence or absence of protection regarding honeybee and other insects visits; the third protected and uncovered when flowers were open, to allow honeybee visits. Worker’s seasonal rhythm of activity, their foraging behavior on flowers, their pollination efficiency, the fruiting rate and percentage of normal seeds were evaluated. Results show that, honeybee foraged on C. macrostachyus flowers throughout its whole blooming period. This bee intensely harvested nectar and pollen. The mean number of individuals foraging simultaneously on 1000 flowers was 21.25 in 2013 and 56.14 in 2014. The mean duration of a visit per flower was 6.07 sec in 2013 and 5.69 sec in 2014. The mean foraging speed was 10.61 flowers/min in 2013 and 12.28 flowers/min in 2014. The fruiting rate and the percentage of normal seeds of unprotected inflorescences were significantly higher than those protected from insects. Through its pollination efficiency, this bee provoked a significant increase of fruiting rate by 44.82% (2013) and 61.85% (2014) as well as the percentage of normal seeds by 78.60% (2013) and 76.69% (2014). The installation of honeybee colonies close to C. macrostachyus populations could be recommended to increase fruit and seed yields and to increase honey production in the region.