Evaluation of morphological characteristics and phenotypic variation of Iranian honeybee (Apis mellifera meda) in Zanjan province

Appearance characteristics of the honeybee are important in identifying races and populations and because of their correlation with production and behavioral traits; they can be used to indirectly improve and reform these traits (Alpatov, 1929; Rinderer et al. , 1982). So, the first step in breeding of the honeybee is to perform morphological studies. In Iran, such studies are necessary for many reasons such as ecological conditions, topography, long beekeeping, and the climate of the four seasons. In 1927, the Russian researcher, Skorikov, identified an independent subtype called Apis mellifera meda, known as the Iranian honeybee, and introduced it to the world (Ruttner et al. , 1985). Tahmasebi (1998) also separated the entire Iranian honeybee population into three subpopulations of the north, west and northwest and central regions. Material and This research was carried out in 2 apiaries of 4 different townships in Zanjan province including Zanjan, Abhar, Mahneshan and Tarom. Identified colonies (40 colonies) include 5 colonies from 8 apiaries, and from each colony 50 (and a total of 2000) Apis mellifera young worker honeybees were collected, in which 800 bees (20 bees per colony) were evaluated. In this experiment, 17 apparent characteristics of the worker bees were evaluated included: the length of the proboscis, the length and width of the front wing, the length of the (a) cubital and (b) cubital veins, the number of right and left wing hooks, the discoidal shift, the length of the femur, tibia and tarsus, over hair, the width of third and fourth Tergitelongitudinal, cubital index, rear length, and the total length of the third and fourth ventral dentures. Measurement of morphological traits was done by routhener method and with the stereomicroscope equipped with eye graded lens. (Goetz, 1959; Dupraw, 1965; Ruttner, 1988). To analyze the variance of the data from the evaluation of traits, eight apiaries as treatments and five colonies of each were considered as repetitions. Analysis of variance was performed in a completely randomized design using MSTATC software. Then, the mean of traits in apiaries was compared with Duncan test. The apiary 1 of Zanjan with the more width of the third and fourth Tergitelongitudinal had the bees larger than bees of the other studied area and bees of the apiary 2 of Zanjan and apiary 1 of Abhar with the less width of third and fourth Tergitelongitudinal were smaller in body size than other bees. The observed difference in the size of bees in the apiary 1 and 2 of Zanjan may be due to the small size of the sample size in this study. The number of right and left wing hooks in the studied apiaries did not show any significant difference. The front wing of most (73%) of the studied bees in terms of the Discoidal shift was in the +1 position. The Discoidal shift feature was studied only by Farshineh Adl (2005) on Apis mellifera bees. The researcher concluded that 82. 5% of the apex wings of Apis mellifera were in the +1 position. Cluster analysis for all morphological characteristics divided the apiaries into two groups: (1) apiary 1 of Mahneshan, apiary 2 of Zanjan and apiary 1 and 2 of Tarom, (2) apiary 2 of Mahneshan, apiary 1 of Zanjan and apiary 1 and 2 of Abhar. In the principal component analysis for the 14 traits, the first and second components justified 50. 5% and 22. 8%, respectively, and in total 73. 3% of the total variation. The first principal component had the largest share in explaining the total variance. Width of wing, (a) cubital and (b) cubital veins, length of thigh, leg, tarsus, T3 and T4 and  left and right hooks were further explained by this component. Therefore, the above-mentioned traits, which are justified by this component, are more important than other characteristics in the distinction between bees in evaluated apiaries. The waist length, cubital index, and the length of the fifth dorsal abdominal hair showed the higher coefficient of determination in the second principal component. In other words, this component largely explains the traits that are of secondary importance. The twodimensional diagram of these two components was drawn, and the apiaries were grouped accordingly. The results confirmed the grouping cluster analysis. The studied apiaries were divided into two groups in terms of the 14 evaluated morphological traits. Width the wing, (a) cubital and (b) cubital veins, length of thigh, leg, tarsus, T3 and T4 and left and right hooks were the most important traits in the differentiation of evaluated honeybees.