Studies on bee populations and some aspects of their foraging habits in Mt. Kenya forest

Abstract

A study was carried out in the Mt. Kenya forest with the objectives of establishing the species diversity of bees, their major pollen and nectar sources and the influence of physical and environmental parameters have on them. It had been established from the literature that the pollinator diversity in the whole of Africa is poorly known and that the conservation of tropical forest flora and fauna could not be adequately done without taking pollinators conservation seriously. Again, a global initiative on pollinator conservation, "the Saulo Paulo Declaration" was established in Brazil in 1999 with the aim to conserve and sustainably use pollinators in agriculture with emphasis on bees. Bees are known to pollinate about 30 % of food crops and 75 % of flowering plants worldwide. Pollination is an important service in maintaining ecosystem integrity and to humanity's existence as well. The study was conducted on the south eastern side of the mountain which covers Kirinyaga district accessed via Kerugoya. The data were collected along a 2.5 - 3 km transects running from the edge of the forest inwards for a period of eight months. A total of 80 species of bee plants and 17 species of bees belonging to five families were recorded. during the study. These families included Apidae, Halictidae, Megachilidae, Anthophoridae, Colletidae and Andrenidae. The common bee plant families included compositae, Rubiaceae, Leguminosae and Labiaitae. The results showed that there was a significant difference (P<0.002) in bee species diversity in four different habitats studied (open woodland, closed woodland, shrub land and pine plantation. The highest species diversity of both bee and bee plants was recorded in the open woodland followed by closed woodland. Pine plantation had the lowest number of bees in terms species richness as well as species diversity. Among the physical factors, light intensity was found to be the most important in bee foraging. A significant difference on bee visitation to flower was found between open and tubular flowers. Bees frequently visited open flowers more than tubular flowers. Yellow flowers were more preferred by the bees as compared to pink-white or purple. It was concluded that the bee community in Mt. Kenya forest faces threat of extinction. The complete absence of sub-family Melliponinae (stingless bees) is still a major question in the conservation of bees in Mt. Kenya forest. Future research and recommendation should include more detailed pollination studies of keystone forest plant species and the effect of forest disturbance on pollinator populations.