Chantal Douka, Fernand-Nestor Tchuenguem Fohouo
Laboratory of Zoology, Higher Teacher Training College University of Yaoundé I, Yaoundé, Cameroon
Laboratory of Zoology, Faculty of Science, University of Ngaoundéré, Ngaoundéré, Cameroon
Key words: Muscadomestica, Ricinuscommunis, flower, nectar, pollen, pollination.
To evaluate the impact of Muscadomestica on fruit and seed yields of Ricinuscommunis, its foraging and pollinating activity were studied in Maroua, during two seasons of flowering (September – November 2010 and 2011). Treatments included unlimited inflorescences access by all visitors, bagged inflorescences to avoid all visits, and limited visits of M. domestica. Observations were made on 10 to 20 inflorescences per treatment of which all flower visitors were recorded. The seasonal rhythm of M. domestica activity, its foraging behavior on flowers, and its pollination efficiency (fruiting rate, number of seeds/fruit and percentage of normal seeds) were recorded. Individuals from 13 species of insects were recorded on flowers of R. communis, after two years of observations. Muscadomestica was the most frequent with 46.07 and 31.70% of visits on flowers in 2010 and 2011 respectively. Muscadomestica intensely foraged pollen in male flowers and nectar in female flowers. In females flowers the foraging speed was 15.09 flowers/min; the foraging activity of M. domestica resulted in a significant increase in fruiting rate by 89.79 and 80.74%; the number of seeds per fruit by 99.02 and 84.21% and the normal seeds per fruit by 76.02 and 75.98%, respectively in 2010 and 2011. This improved performance is justified by the positive action of M. domestica on the pollination of flowers of R. communis.