Bee Diversity and some Aspects of their Ecological Interactions with Plants in a Successional Tropical Community

Abstract

This study aimed at establishing bee diversity and some aspects of their interactions with plants along a forest regeneration gradient in Kakamega Forest. To determine the bee diversity, bee samples were collected with the help of sweep nets along belt transects for a period of two years, that is, May 2002 to April 2004. In addition, more data on bee species was collected from the existing past records and bee collections from National Museums of Kenya. In total, 243 species of bees represented in four families, of which 234 were sampled in Buyangu Nature Reserve were recorded during the study. These families included Apidae, Halictidae, Megachilidae and Colletidae.<br /> In addition, 40 families of representing 189 species of plants were found to support the bee community. The most important plant families included Acanthaceae, Asteraceae and Papilionaceae. A high degree of resource sharing based on niche overlap results was observed between the highly eusocial and the dominant solitary bee species, although the eusocial bees showed the largest niche breadth. Similarly, generalization was more pronounced among the eusocial bees as compared to solitary bees. The results from this study agreed with the expected trend of increased diversity in secondary forests as compared to mature forests. In contrast, generalization was found to increase with forest maturity. <br /> In conclusion, the study clearly indicates that bees require a diversity of microhabitats. Secondary forests and surrounding farming areas offer the best refugia sites for bees. On the other hand, the bees cannot survive without the forest for it offers nesting sites and abundant floral resources especially during the dry season when there are no flowers in the open areas. Based on the current results, Kakamega Forest stands out as one of the best bee hot-spots in East Africa. <br /> The study advocates further research in pollination biology of wild plants especially on rare plants given that a high level of generalization was documented among the eusocial and solitary bees but little is known on plants’ perspective. Finally, I wish to recommend further research on whether natural forest regeneration process should be altered in some forest patches in order to maintain some secondary forests.