Genetic and morphometric variation in honeybee (Apis mellifera L.) populations of Turkey

Apidologie Genetic and morphometric variation in honeybee (Apis mellifera L.) populations of Turkey n KANDEMIR 0 l KENCE 0 Aykut KENCE 0 0 Department of Biology, Middle East Technical University , 06531 Ankara , Turkey - Six enzyme systems were studied to determine the genetic variability in honeybee populations in Turkey. Ten morphometric characters were also measured to determine the extent of morphometric variation. Out of six enzyme systems, four were found to be polymorphic with 16 allozymes. The average heterozygosity was calculated as 0.072 ± 0.007. Morphometric and electrophoretic variables were equally effective in discriminating honeybee populations. European and Anatolian honeybees were separated on the first axis, and Anatolian honeybees were further separated along a second canonical axis. The observation of rare alleles in isoenzymes, detection of high genetic diversity and the presence of four known subspecies support the argument that Anatolia has been a genetic center for honeybee populations in the Near East. 1. INTRODUCTION Ruttner [ 30 ] claimed that southwest Asia is a zone of high morphological diversification and evolution for honeybees. Many clearly distinct races have evolved within this region, which includes a diversity of habitats. Asia Minor, including Anatolia, appears to be the genetic center for these honeybee subspecies according to the multivariate statistical analysis of morphometric data [ 30 ]. Honey bee races in this region include the subspecies Apis mellifera anatoliaca, A. m. caucasica, A. m. meda, and A. m. syriaca, which were considered by Ruttner [ 30 ] to form a basal branch (O) of the species. Another subspecies that is found in the European part of Turkey, i.e., Thrace, may be A. m. carnica, which belongs to the branch C of Ruttner’s classification. Migratory beekeeping has become widespread in Turkey within the last 20–30 years. Thousands of colonies are overwintered in the Mediterranean and Aegean regions, and then moved to central and eastern Anatolia during the summer and fall. These practices might promote the gene flow between different races, and result in homogenization of the gene pool of Anatolian honeybees. Despite the apparent importance of Anatolia in the evolution of honeybees, very little work has been done on the morphological and genetic diversity of Anatolian honeybees [ 14, 37 ]. In this study, we aimed to determine the extent of morphometric and genetic variation of honeybees distributed widely across Turkey. Ten morphometric variables were measured, and electrophoretic variation was studied in six enzyme systems. 2. MATERIALS AND METHODS Honeybee samples were collected in 1994–1996 between March and September in Turkey. Samples were taken from 77 different locations in 36 provinces from different geographic regions of Turkey. Turkey is divided into seven geographic regions differing both in climatic conditions and in geological structure. Sampling was carried out mostly from small apiaries which do not practice migratory beekeeping, and the hives sampled were stationary during the MarchSeptember sampling period. Requeening of colonies was mostly natural, although some beekeepers reported that occasionally queens had been purchased for some colonies. In all cases we attempted to sample colonies that had no history of management for requeening. Special care was taken to sample from localities that were not frequented by migratory beekeepers. Approximately 3 000 worker bees were collected, and were put into small plastic bottles, which were labeled; the insects were fed either with honey cake (honey and powdered sugar [1:1]) or with ‘Turkish delight’ (water + saccharose + starch), and brought live to the laboratory. Honeybees were dissected, the thoraces were ground, and the homogenates were kept frozen until needed for electrophoresis. Forewings and hind legs were mounted on a microscope slide for morphometric analysis. Microscope slides of legs and wings were projected onto a TV screen, and measurements were taken. In the present study, ten morphometric characters were measured, i.e., four for the hind legs, four for the forewings (according to Ruttner [ 30 ]), and an additional two forewing characters, distance c and distance d as determined by Nazzi [ 20 ]. Six enzyme systems (esterase: 3.1.1.1; hexokinase: 2.7.1.1; malate dehydrogenase: 1.1.1.37; malic enzyme: 1.1.1.40; phosphoglucomutase: 2.7.5.1; and phosphoglucose isomerase: 5.3.1.9), known to be polymorphic in A. mellifera, were utilized as biochemical markers. Starch-gel electrophoresis, gel and sample preparation and experimental conditions have been reported previously [ 14 ]. All allozymes were designated by using relative mobilities, with the most common allozyme used as standard (relative mobility: 100). Gene frequencies, enzyme heterozygosities and population heterozygosities were calculated according to Nei [ 22 ], using BIOSYS [ 39 ]. Goodnessof-f (...truncated)