ABSTRACT
French bean (Phaseolus vulgaris L.) is an important crop with high impact on rural
employment and livelihood. In Kenya, the crop is grown for export by small scale
farmers in high potential areas of Central, Rift valley and Western regions. These
regions are densely populated leading to intensive farming and land fragmentation,
which research has reported to be among the major threats of bee pollinators.
However, amongst the known constraints, pollination has not featured amidst many
farmers, a fact associated with lack of knowledge on the same. The crop benefits from
bee pollination through improved pod set and pod quality. The objectives of this study
were to assess the taxonomic composition and diversity of bees visiting flowers of
French beans, assess the abundance of bees visiting flowers of French beans,
investigate the effect of diversity and abundance of bees on the yield of French beans,
determine the effect of time of the day on the trends of the most common bee genera
visiting flowers of French beans. Field surveys were conducted on Julie cultivar of
French beans in Kaitheri and Kangaika locations of Timau division (Likipia
County).The study design was based on a protocol developed and agreed upon by
global partners for testing pollination deficit in crops. Ten farms were selected along a
3 km transect, where five farms were located at 0.2 km from the edge the forest and
other five were at 1 km distance. Sampling was done on a plot measuring 760 m2,
once a week, between 8.00 to 10.00 h and 11.00 to 2.00 h, three times a season at a
weekly interval, in the years 2011 and 2012. Sampling was done on 6 rows each
measuring 25 m x 2 m for 30 minutes. Sampling of bees to assess taxonomic
composition and diversity was done using sweep net. Sampling of bees to assess
abundance was done using two scanners, where one scanner counted newly opened
flowers and another one counted bees in the flowers. Effect of diversity and
abundance of bees on yields of French beans was done by daily weighing and
recording of production inputs and outputs of French beans. Observation of bees to
determine the effect of time of the day on the trends of the bees was done on six
farms, where, each group of two farms was at 0.2 km, 0.8 km and 1 km from the edge
of the forest. Bees were observed from 06.00 h to18.00 h and recorded on hourly
basis. Results on diversity of bees revealed five families, nine genera and twelve
species of bees during the study period of two years. Total diversity of bees sampled
on farm located at 0.2 km and 1 km were not significantly different (P=0.161). Mean
numbers of bees sampled on farms located at 0.2 km and 1 km were not significantly
different (P=0.821). The mean number of Apis mellifera was higher than those of all
other bee species. The mean number of Apis spp was higher than those of Xylocopa
spp and Megachile spp. The total diversity and abundance of bees did not
significantly affect the total yield of French beans. Yield of French beans only
correlated significantly with the abundance of Xylocopa spp. Bees of Apis spp foraged
on flowers of French beans between 08.20 h and 17.00 h, with a peak activity between
10.30 h to 11.00 h. Bees of Xylocopa spp foraged on flowers of French beans between
08.20 h and 15.00 h, with the peak activity at 14.00 h. Bees of Megachile spp foraged
on flowers of French beans between 09.00 h and 16.00 h, with the peak activity at 13.
00 h. Thus, this study recommends implementation of bee friendly practices and measures to enhance pollination of crops.
D., M (2021). Diversity And Abundance Of Bees And Their Effect On Yield Of French Beans, Adjacent Mt Kenya Forest In Laikipia County. Afribary. Retrieved from https://afribary.com/works/diversity-and-abundance-of-bees-and-their-effect-on-yield-of-french-beans-adjacent-mt-kenya-forest-in-laikipia-county
D., MASIGA "Diversity And Abundance Of Bees And Their Effect On Yield Of French Beans, Adjacent Mt Kenya Forest In Laikipia County" Afribary. Afribary, 02 Jun. 2021, https://afribary.com/works/diversity-and-abundance-of-bees-and-their-effect-on-yield-of-french-beans-adjacent-mt-kenya-forest-in-laikipia-county. Accessed 12 Oct. 2024.
D., MASIGA . "Diversity And Abundance Of Bees And Their Effect On Yield Of French Beans, Adjacent Mt Kenya Forest In Laikipia County". Afribary, Afribary, 02 Jun. 2021. Web. 12 Oct. 2024. < https://afribary.com/works/diversity-and-abundance-of-bees-and-their-effect-on-yield-of-french-beans-adjacent-mt-kenya-forest-in-laikipia-county >.
D., MASIGA . "Diversity And Abundance Of Bees And Their Effect On Yield Of French Beans, Adjacent Mt Kenya Forest In Laikipia County" Afribary (2021). Accessed October 12, 2024. https://afribary.com/works/diversity-and-abundance-of-bees-and-their-effect-on-yield-of-french-beans-adjacent-mt-kenya-forest-in-laikipia-county