Browsing by Subject "Apiculture"

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Classification and characterization of Ethiopian honey bees (Apis mellifera) based on morphometric, genetic and socio-economic analyses
(2022) Hailu, Teweldemedhn Gebretinsae; Hasselmann, Martin
Ethiopia is a major beekeeping country located in northeast Africa where several evolutionary lineages of Apis mellifera contact. A unique practice of honey bee colony marketing which involves broad agro-ecological zones (AEZs) is a developing trend in the northern part of the country such as Tigray region in association with apicultural development. Several studies based on classical morphometry on the Ethiopian honey bee subspecies classification debated from the unique Apis mellifera simensis to five others. Moreover, the genetic diversity, adaptation, gene flow and inter-relationships of the honey bees between AEZs were not disentangled – a challenge for planning sustainable apicultural development and conservation. Therefore, this study was conducted to elucidate the honey bees of Ethiopia in a context of apicultural transformation using integrated methods: morphometrics, genetics, colony market survey and metadata analyses on beekeeping development. The results of geometric morphometric analyses confirmed that Ethiopian honey bees represented by Apis mellifera simensis references belong to a separate lineage (Y) compared to A, O, M and C, and the present sample belonged to Y. This supported the hypothesis of five major honey bee lineages of the honey bee Apis mellifera. Similarly, a maximum likelihood phylogenetic tree analysis based on the mitochondrial COI-COII showed that most of the Ethiopian honey bees belong to lineage Y. However, a substantial proportion of the samples from the northern part of the country clustered with lineage O, which support the hypothesis that there is close contact between Y and O. Both geometric morphometry and classical morphometry differentiated the Ethiopian honey bees from all references including A. m. monticola, A. m. scutellata, A. m. jementica, A. m. adansonii but grouped with A. m. simensis. Genetically, five DraI haplotypes (COI-COII) were found to be randomly distributed across AEZs, indicating a substantial gene flow. Consequently, the level of genetic differentiation among the Ethiopian honey bee subpopulations defined by local areas and AEZs was generally low based on r7-frag nuclear marker, which is identified to be associated with adaptation to habitat elevation in East African honey bees. Similarly, nucleotide diversity consistently decreased with increasing elevation – indicating a reduced effective population size in the highlands. Results obtained from colony market survey showed that the honey bee swarms are reproduced in a few highlands and re-distributed throughout the region. Colony buyers have preferences of color and AEZ of origin of the honey bees, which led to a one-way flow and eroded the overall level of genetic differentiation. However, a marked differentiation was detected between the highland and lowland honey bees in relic communities where an allelic length polymorphism was observed as a signature of local adaptation. Altogether, Ethiopian honey bees belong to the lineage Y and subspecies A. m. simensis, and are characterized by a high level of gene flow enhanced by colony marketing; but a conserved signature of local adaptation to higher elevations was identified in less disturbed communities. Further studies based on genome-wide analyses and field experiments, focusing on undisturbed communities, can provide more insights into adaptation, admixture and management implications. Sustainable bee breeding and extension services that enable local beekeeping without colony trade and transportation will help to promote apiculture and genetic conservation.