Soluble proteins in Messor structor (Latreille, 1798) (Hymenoptera: Formicidae) populations from Bulgaria - genetic variability and possible usage as population- genetic markers

The genetic variability of ant species determined as Messor structor (Latreille, 1798) or close to it ("M. cf. structor") from Bulgaria has been studied using polyacrylamide gel electrophoresis analysis of five soluble protein systems (Sp-1, Sp-2, Sp-3, Sp-4 and Sp-5) corresponding to 5 loci. Four of the studied loci were found to be polymorphic. Two alleles were detected at Sp-1 and Sp-2 loci and three - at Sp-3 and Sp-5. The observed and expected heterozygosities (Ho and He) ranged from 0.0 (Yambol) to 0.140 (Topolovo) and from 0.170 (Nova Zagora) to 0.401 (Tvarditsa), respectively. The calculated mean value of inbreeding coefficient (FIS) was 0.8263 and demonstrated high level of inbreeding within populations, which correlated with a low level of observed heterozygosity compared to the expected one. The estimated mean fixation index (FST) value was 0.2746. Allele frequencies of soluble protein loci were used to estimate Nei's (1972) genetic distance and to obtain the Unweighted Pair Group Method with Arithmetic Mean (UPGMA) and Neighbor-Joining (NJ) dendrograms, where Topolovo and Nova Zagora populations were grouped separately than other populations.