Pollination efficiency of Xylocopa torrida Westwood 1838 (Hymenoptera, Apidae) on Mimosa pudica Linnaeus 1753 (Fabaceae) inflorescences at Yassa (Douala - Cameroon)

Abstract

At Yassa, from 2014 to 2015, flowers of Mimosa pudica were observed for the study of the foraging behavior of insects and the determination of the impact of these arthropods on pod or seed yields. Two treatments were determined from labeling of 120 inflorescences. Treatments were differed according to whether ridges or the inflorescence were protected or not against insect visits. A third treatment was made up of 50 inflorescence that were protected then exposed exclusively to X. torrida visits when flowers were opened. The foraging and pollination activity of insects and the apicultural value of the plant were studied. On 13 insect species recorded on flowers of M. pudica, X. torrida was the most represented insect with 35.41% of 401 visits. This carpenter bee harvested intensely the pollen. The activity of insects started around 7 am and ended around 2 pm, with a peak between 10 am and 11 am. Insects were faithful to the flowers of this plant during foraging bouts. Data obtained allow the classification of the plant between the highly polliniferous. Insects improved the yields of this plant. The pollination efficiency of X. torrida has signicantly increase the number of fruits per inflorescence by 52.31% and 53.17%, the number of seeds per pod by 5.68% and 4.26% and the percentage of the normal seeds by 7.78% et 6.02%, respectively in 2014 and 2015. M. pudica can be cultivated and protected to increase pollen production as a honey bee hive product. The conservation of Xylocopa nests near the population of M. pudica is encouraged to increase fruit and seed yields in the region.