Experiments were conducted for studying the foraging behaviour of a blowfly species Chrysomya putoria (Diptera: Calliphoridae) on Ricinus communis (Euphorbiaceae) in a Sudano-Sahelian area of Cameroon in 2017 and 2018. To do so, castor bean plants were flagged and fly foraging parameters were recorded. The effects of blowfly activity on pollination and fruiting rate of R. communis were estimated by comparing unrestricted and restricted racemes. Chrysomya putoria accounted for 82.33% of the total number of flower visits among the 15 anthophilous insects recorded. Pollen and nectar foraging occurred throughout the day, with a major peak at 8-9 am. The density of foragers was about 300 individuals per plant. The mean duration of a flower visit for male and female flowers was significantly different and resulted in a foraging speed of 3-5 flowers/minute which increases cross-pollination of R. communis. The floral activity of C. putoria improved the fruiting rate of castor bean by about 11% and conversely, this plant appeared as an important food source for the conservation of its main flower-visitor. Castor bean and the blowfly species seem to have a mutualistic relationship.
Keywords: blowfly, castor bean, cross-pollination, geitonogamy, insect-assist anemophily, yield.