Relating bee activity to pollination of Luffa aegyptiaca Mill. in Ghana

Abstract

SummaryLuffa aegyptiaca (Cucurbitales: Cucurbitaceae) is a plant of economic importance in Ghana and in other parts of the world, especially in tropical and subtropical regions. Cultivation of the plant in Ghana has reduced over the last two decades, so it now mostly grows in the wild. A survey was conducted in coastal Ghana to provide baseline information about pollinators of the plant, to inform decisions on the conservation of it and its pollinators. Apis mellifera, three species of Xylocopa and two of Amegilla were identified among the flower visitors as likely pollinators. Preliminary measures of the efficiency of these visitors as pollinators were made and the relationship between visitor behaviour and the phenology of the plant was studied. Flowers were open for about 10 h, and over 80% of female flowers received pollen within the first 3 h of opening. Out of 120 female flowers observed, A. mellifera visited 49.2%, Xylocopa spp visited 35.8% and Amegilla spp visited 15%. Xylocopa spp visited flowers early in the day, were most active during the period that most flowers received pollen, and deposited pollen on stigmas of all female flowers they visited. Whilst a single visit by Xylocopa spp or Amegilla spp. could leave enough pollen for fertilization and fruit formation, multiple visits by A. mellifera might be required for successful pollination to occur. These results suggest that Xylocopa and Amegilla are more efficient pollinators of L. aegyptiaca than A. mellifera. The importance of these findings for the conservation of the plant and its associated insect species are discussed.