The Importance of African Honey Bees (Apis Melifera L.) As Pollinators of High Value Crops in Kenya: A Case of Butternut Squash (Cucurbita Moschata Duchesne

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Kasina M.
Kraemer M.
Nderitu J.
Martius C.
Wittmann D.
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Butternut squash (Cucurbita moschafa Duchesne ex Poir.) is a high value crop in Kenya grown mostly by pollination smallholder farmers as a main source of household income, targeting urban market. Prior to this study, there was no information about its pollinators in the country and farmers do not manage its pollination. We documented butternut squash flower visitors and their behavior during foraging periods and evaluated their pollination efficiency in terms of yield as the end point. The study was done at Kakamega, a high potential area for agriculture in western Kenya where butternut squash seeds were planted in 15m xl5 m plot. About 50 flowers were bagged to prevent pollinators while a similar number was left open for unlimited visits. Individuals of honey bees (Apis mellifera L.), Halictid bees (Halictidae), stingless bees (Hypotrigona spp), ants (Formicidae) and hover flies (Syrphidae) were observed visiting flowers. It was only honey bee visitation that was sufficient to effectively pollinate butternut squash flowers. Higher honey bee visitation rates were observed on female flowers compared with male flowers. Fruit and seed yields were significantly higher (P<0.05) in flowers with unlimited bee visits compared with hand pollination possibly due to challenges in timing pollen maturity and stigma receptivity. This study shows that honey bees should be protected to ensure crop (butternut squash) pollination. The recent reports of declining honey bee colonies due to parasites and diseases, climate change, pesticide use and reduction of food resources should be taken seriously as this threatens crop production and hence food security. Farmers growing butternut squash are advised to keep or rent honey bees for pollination of their crop during blooming period to guarantee them quantity and quality yields. In addition, policies to support use of honey bees for crop production in Kenya should be developed and implemented to ensure information on pollination of crops including butternut squash forms part of the extension messages to farmers.
East African Agricultural And Forestry Journal, 79 (3), p. 143-149