The complimentary role of wild habitats in crop pollination: a case study on the eggplant (solatium melongena l., solanaceae)

Abstract

In this study, carried out in Nguruman, southwestern Kenya, 10 bee species were identified as eggplant pollinators. Their foraging behaviour was shown to be affected by the prevailing ambient temperature and not time of the day or the number of flowers per square meter in the eggplant fields. Only 2 bee species, Xylocopa caffra and Narnia sp., visited the eggplant blossoms at a great frequency. Their pollinator effectiveness was determined in two eggplant cultivars (the Black Beauty and the Early Long Purple). X caffra proved to be the most effective pollinator of the eggplant. Floral manipulations performed to study the most effective mode of pollination in the eggplant revealed that although the eggplant is self-compatible, it needs efficient pollinators for fruit set. Flowers that were hand pollinated with pollen from their own anthers resulted in fruits with high seed set. The eggplant therefore needs an effective mode of pollination to transfer the pollen from the anthers to the stigmas. Seed set in fruits of open-pollinated flowers were higher than in self-pollinated flowers but not as high as in hand-pollinated flowers Alternative forage resources that the pollinators foraged were also determined. A total of 12 plant species were identified over a five month period along a transect that traversed the surrounding wild habitat. The most preferred alternative flowering plants such as Duosperma kilimandscharicum, Commicarpus helenae and Justicia jlava were mainly found in the farm area which was highly foraged throughout the study period. The riparian forest was also highly foraged in some months. The farm areas and the riparian forest should therefore be maintained because they provide alternative forage and nesting sites for the eggplant pollinators. Fragmentation of the habitat would lead to loss of pollinators and a subsequent reduction in the yield of the eggplant