Sampling and DNA extraction
We sampled a total of 408 B. terrestris workers from fourteenpopulations in the Mediterranean region in Turkey (Table 1). To assess the genetic structure of native and commercial populations and the potential impacts of introducing non-native subspecies (or populations), we divided the sampled populations into three groups;1) greenhouses (commercial) populations 2) nearby greenhouses and 3) far from the greenhouses populations. A total of 212 worker samples (one worker bee per commercial hive) from seven different commercial companies (belonging to all local and global companies, CP1-CP7) were collected from greenhouses populations. A total of 100 worker samples from four populations (AK, KU, DE and GB-at least 30 km away from each other) were collected within the 5 km areas surrounding the greenhouses where commercial B. terrestris colonies are intensively used for crop pollination. A total of 96 worker samples from three native populations (TM, FS, BB) were collected in the best preserved areas more than 30 km away from greenhouses and each other. In a previous study, Ozbek (1997) observed native B. terrestris populations all areas in which we collected field worker samples (seven locations) before the use of commercial B. terrestris colonies in Turkey. All sampled workers were stored in 95% ethanol solution at -18 ° C until DNA extraction. Total genomic DNA was extracted from thorax muscles of each worker bee using a 10% Chelex solution (Walsh, Metzger, & Higuchi, 1991).