Bee pollination enhances crop yield and fruit quality in Kakamega , Western Kenya.

Abstract

In Kenya small-holder farmers, who form the main agricultural producers, do not manage pollination but rely on the wild to provide pollination services. With continued habitat fragmentation, there is likelihood of pollinator decline in the country as more land is cleared for agriculture. This study investigated dependence of some crops on bee pollinators as a cautionary measure to the populace on the need to manage pollinators. Nine crops were planted in individual plots of 15 x 15 m where yield from bagged and un-bagged (bee pollinated) flowers were compared. Dependence of a given crop on bee pollination was based on productivity model (effects on quantity) and market model (either quantity or quality as determined by demand for the commodity). The dependence values ranged from 14 to 99%, with higher values recorded when analyses were based on market model compared with productivity model. Crops that are otherwise assumed not to need bee pollination such as legumes had significantly higher yields when provided with bees. Honey bees (Apis mellifera) were effective pollinators of sunflower and squash. However, wild bees, carpenter bees (Xylocopa spp) and leaf-cutter bees (Megachile spp), were the most effective pollinators of tomato, beans, cowpea, and passion fruit. From the dependence-on-bee-pollinators perspective, it is clear that crops pollinated by the wild bees risk huge yield losses if these bees are not conserved. This has effect on family income, food security and Kenyan economy, which is largely agricultural based. The findings strongly suggest that pollinators are an important component of rural Kenyan agricultural productivity. It is evident that even slight margins of yield are likely to have significant effects on market and nutrition when measured over a longer term.