Diversity and feeding behaviour of insects visiting Brachiaria ruziziensis (Poaceae)

The diversity of visitors to flowers of the grass Brachiaria ruziziensis R. Germ and Evrard is very low in Ngaoundéré, Cameroon. Bees (Hymenoptera) and syrphids (Diptera) were observed gathering pollen, and each insect group had its own strategy depending on the prevailing environmental conditions. Syrphids are early-morning flower visitors and take time to feed on wet pollen. They visit flowers from 0630 h when the relative humidity is higher than 80% and temperature lower than 25°C. Bees gather dry pollen from 0930 h when the relative humidity is < 50% and temperature > 30°C, and carry it to the nests for feeding. © ICIPE 2005.