| dc.description.abstract | Background: The honeybee (Apis mellifera L.) is an important insect that produces honey wax and royal
jelly, and propolis that thought to fight infections. It also acts as a cross pollinator of both agricultural
and wild plants. However, honeybee colonies are presently faced with a number of constraints both
globally and locally. Like in many parts of the world, hive colonization and honey yields in Transmara
West Sub-County of Kenya have been on a decline; attributed partly to increased pesticide use. This study
thus set out to establish the impacts of pesticides use on honeybee mortality rate and honey production
by screening honeybee, honey and pollen for pesticide residues.
Methods: A longitudinal descriptive survey and experimental design was adopted for the study. Sixteen
apiaries were selected and two strong colonies in Langstroth hives identified in each apiary. These were
replicated once to bring the total to 64 colonies, which acted as controls and treatments. Traps were fixed
at hive entrances to aid in collection of dead bees at weekly intervals for a period of six months (March to
October 2015). Samples of honeybee colony matrices among them pollen loads, honeybee and honey
were collected from the identified colonies and analyzed for amitraz, chlorfenvinphos, cypermethrin,
deltamethrin and malathion residues using Queshers method at Maseno University chemistry
laboratories.Differences in honeybee mortality rate and honey yields between experimental sets were
established by one way ANOVA followed by a Turkey HSD post hoc test. A structured questionnaire was
also administered to select bee keepers to evaluate their perception on and role in pesticide use. Their
responses were analyzed using the χ
2
test or Fisher's exact test.
Results: Mortality rate in treated colonies (229±5.1) was significantly higher than in control colonies
(73±11); MSD=4.6791, p=0.01. Likewise, honey yield in control colonies (16.0±1.0 kg) was significantly
higher than in treated colonies (8.7±1.2 kg); (MSD=4.8425, p=0.024). For instance, the average season
one honey yield in the control colonies was 18.0 ± 1.0 kg compared to 7.1 ±1.10 kg, 8.4 ±1.50 and 9.2
±1.7 kg, in treated colonies. This implies that increased pesticide use may have contributed to increased
honeybee mortality rate and reduced honey yields. No residues were detected in all honeybee colony
matrices, implying that honeybee products within the study settings were safe for consumption. Majority
of farmers reported observing changes in honeybee colony strength, a reduction in honey yields, reduced
colony size, significantly weakening the colonies.
Conclusion: This study established an inverse relationship between pesticides use honeybee mortality
rate, with significant increase in mortality rate and reduced honey production being associated with its
use. Absence of residues in the matrices in all the studied sites suggests honeybee products from the
study setting are still safe for human consumption. Nevertheless, farmers need to be trained on safe
handling of pesticides. In addition, there is need for further research on the synergistic impacts of
pesticides use on honeybees, and the need for alternative and ecofriendly pest control options to curb the
challenge associated with indiscriminate effects of pesticides on other important insects like honeybees. | en_US |
