Masters Thesis

The impact of honeybees on coffee pollination in Jamaica, West Indies

Crop pollination by wild bees is an ecosystem service of great value, particularly in heavily developed tropical settings. Self-fertile Coffea arabica is an important cash crop for many tropical countries. I used pollinator surveys and exclusion experiments to estimate the potential ecosystem service provided by non-managed bees on two coffee farms over two years in Jamaica, West Indies, and to examine the role that relatively undisturbed natural habitat plays in providing this service. Bee diversity was low at my study sites; only eight native species were captured via aerial netting and pan trapping, and meliponine bees were absent. Ninety four percent of all visits to coffee flowers were made by feral, non-Africanized Apis mellifera. Visit rates were high, and flowers received an average of 6 – 48 visits per hour depending on florea (flowering burst). These visits increased coffee yield substantially; open-pollinated flowers received more pollen than bagged flowers, which translated to a 25.6% and 15.6% increase in fruit set and fruit weight, respectively. The value of pollination services to farmers ranged from $297-517/ha depending on farm and price paid per box. In contrast to comparable studies elsewhere, visit rates were not related to distance from forest edge and they showed a very weak relationship to yield. Additionally, yield was not limited by insufficient pollination. These results show that even though the Jamaica coffee-growing landscape does not support high bee diversity, it nevertheless provides high quality pollination service in the form of feral honeybees. Moreover, the results should provide a strong economic incentive for farmers to foster habitat that provides nest sites for honeybees as well as year-round floral resources.

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