DIURNAL VISITATION OF FLOWERS OF COWPEA BY INSECT POLLINATORS WITH EMPHASIS ON THE WESTERN HONEYBEE, APIS MELLIFERA, IN BAUCHI, NIGERIA

In order to study the diurnal visitation of flowers of cowpea by insect pollinators, the number of open flowers of cowpea and the kind and number of insects visiting the flowers were recorded for a period of 5 minutes and at intervals of 1 hour from sunrise to sunset in a quadrat of 1 m² placed randomly on a cowpea farm. Cowpea flowers were observed to open from 6:00 hour to 13:00 hour, daily. A total of 388 open flowers and 256 insect visitors were recorded during the 7-day period of the study. 52.3% of the visitors belonged to the order Hymenoptera (honeybees, wasps, and ants), 26.2% to Lepidoptera (butterflies and moths), and 21.5% to Diptera (flies). Among the hymenopterans, 42.3% were honeybees, 40.9% ants, and 16.8% wasps. The results of this study suggest that in every hour approximately 47,000 insect pollinators (including 9,800 honeybees) were exposed to insecticide in every hectare of flowering cowpea if spraying was done between 6:00 hour and 13:00 hour. Thus, to minimize the impact of insecticides on these beneficial insects, cowpea fields should be sprayed from 14:00 hour and beyond.