Insights into Ethiopian honey bee diversity based on wing geomorphometric and mitochondrial DNA analyses

Abstract

Traditional beekeeping has been playing important socio-economic roles in Ethiopia for millennia. The country is situated in northeast Africa, where ranges of major evolutionary lineages of Apis mellifera adjoin. However, studies on the classification and distribution of subspecies and lineages of honey bees in the country are partly inconsistent, either proposing multiple subspecies and lineages or a unique A. m. simensis. This study was conducted with the aim of elucidating Ethiopian honey bees in reference to African subspecies and major global lineages using wing geometric morphometrics and COI-COII mitochondrial DNA analyses. For this purpose, 660 worker bees were collected from 66 colonies representing highland, midland, and lowland zones in different locations. Both methods indicated that the samples from this study form a distinct cluster together with A. m. simensis reference. In addition, forewing venation patterns showed that most of the Ethiopian samples are separate from all reference subspecies, except A. m. simensis. Analysis of COI-COII sequences revealed five DraI haplotypes (Y2, Y1, A1, and O5’), of which one was new denoted as Y3. Moreover, centroid size strongly associated with elevation. In conclusion, the results supported that Ethiopian honey bees are distinct both at lineage and subspecies levels; however, there is an indication of lineage O in the north.

Disentangling Ethiopian Honey Bee (Apis mellifera) Populations Based on Standard Morphometric and Genetic Analyses

“…These honey bees have been described as a unique evolutionary lineage [3] and a subspecies [15] that differs from the honey bee populations in the neighboring countries. This was supported by a recent study on forewing geometric morphometrics and mitochondrial DNA analyses [16]. Geometric morphometry based on forewing venationinherited from both parental lines-can efficiently separate honey bee populations [38][39][40], whereas the mitochondrial genomic region commonly known as COI-COII varies among honey bee lineages in sequence length and the frequency of characteristic P and Q motifs, which can provide sufficient information to elucidate evolutionary history of maternal lineages [41].…”

“…Samples of 660 worker honey bees out of 66 managed colonies were collected from nine sites in Tigray regional state (north) and two sites in the Wendogenet local area (south), representing highland, midland and lowland AEZs of Ethiopia (Table S1). Details on sampling and study sites are provided in [16]. The samples were imported to the University of Hohenheim (Germany) in compliance with formalities stipulated by the Ethiopian Institute of Biodiversity (reference code of permit letter: EBE71/160076/2018) and subjected to morphometric and genetic analyses.…”

“…In particular, there have been controversies in the classification, distribution and characterization of honey bee populations in northeast Africa and the Middle East among morphometric and molecular studies [1- 3,7,13,14]. Ethiopian honey bees have been discriminated from neighboring populations and designated as a unique lineage and subspecies after decades of inconsistencies [3,15,16]. Former studies reported several subspecies in the country, including A. m. jemenitica, A. m. scutellate and A. m. monticola [17][18][19].…”

“…Geometric morphometry based on forewing venationinherited from both parental lines-can efficiently separate honey bee populations [38][39][40], whereas the mitochondrial genomic region commonly known as COI-COII varies among honey bee lineages in sequence length and the frequency of characteristic P and Q motifs, which can provide sufficient information to elucidate evolutionary history of maternal lineages [41]. Hailu et al (2020) [16] provided insights into evolutionary lineages, subspecies and mitochondrial haplotypes of Ethiopian honey bees based on AEZs and geographic location using forewing geometric morphometry and COI-COII.…”

Challenges and perspectives for beekeeping in Ethiopia. A review

“…Classification and geographical distribution of Ethiopian honey bees have been intensively discussed within the research community but methodological variations have been leading into contrasting results and opinions. While some recently published articles based on mitochondrial DNA analysis described the Ethiopian honey bees, with their evolutionary lineage Y, to be genetically distinct from other A. mellifera subspecies in neighbouring geographic areas (Boardman et al 2020;Franck et al 2001;Tihelka et al 2020), Hailu et al (2020) reported of maternal lineage O to be present in northern Ethiopia. Morphometric analysis investigating present subspecies was also not in agreement with each other (Amssalu et al 2004;Hailu et al 2021;Meixner et al 2011;Nuru et al 2002a;Radloff and Hepburn 1997;Ruttner 1988).…”