Determination of genetic characteristics of native and commercial bombus terrestris (Hymenoptera: Apidae) populations by using microsatellite markers and mtDNA

Bombus terrestris L. is the most common bumble bee species found in Turkey and especially in the Mediterranean Region natural fauna. On the other hand B. terrestris is reared extensively today on a mass scale and is widely spread commercially in many countries including Turkey where it is used as a pollination agent. Approximately 300 000 commercially produced B. terrestris colonies have been used every year in Turkey. In this study, a total of 408 worker bee samples were collected from 7 native B. terrestris populations (Aksu, Kumluca, Demre, Geyikbayırı, Termesos, Bayatbademler and Faselis) and 7 commercial reared populations (TP1-TP7). The genetic characteristics of the native B. terrestris populations were investigated by using twenty microsatellite markers and two mitochondrial genes (COI and cytb). Microsatellite analysis showed adequate levels of genetic diversity in both commercial and native populations, while base on the Pairwise FST values genetic differentiation between populations did not differ significantly (0.014-0.045; p> 0.05). Depending on the heterozygous deficiency, populations deviated from Hardy-Weinberg equilibrium due to high inbreeding (mean Fis: 0.234). According to the best K value in structure analysis, the populations are separated into four distinct clusters. However, there are transitions between these four main clusters and it has been determined that populations could not been clearly separated from each other. In mtDNA analysis, two haplotypes for COI gen region and six haplotypes for cytb gene region were found. In mtDNA analysis, genotypes belonging to the subspecies B. t. dalmatinus were determined in all populations, while genotypes belonging to the subspecies B. t. terrestris were intensively determined in some commercial populations and nearby greenhouse populations. Our results imply that native bumble bee populations interact with commercially produced bumble bees. These findings support concern about gene flow between populations and altering the genetic structure of native bumble bee populations in recent years.