Genetic diversity and multilocus structure in sexual Otiorhynchus alpicola populations (Goleoptera: Gurculionidae)

Otiorhynchus alpicola Boh. (Coleoptera: Curculionidae) is distributed on high mountains of central, southern and south-eastern Europe. On the Balkan peninsula, this species is patchily distributed on mountain peaks at heights over 1800 m. To examine the organization of isoenzyme variation of the ten sexual (diploid) populations, starch gel electrophoresis of enzymes was used. The average heterozygosity over 14 gene loci was 0.11. For diploid O. alpicola, F-statistics were used to assess population heterogeneity and substructuring. The data indicate that, compared with other insects, this high-altitude weevil species is genetically very differentiated (the average F _ST= 0.35). In addition, gene-flow among populations was extremely low (the estimates of N_em from Wright's F _ST and Slatkin private-allele methods were 0.47 and 0.83, respectively). Pairwise linkage disequilibrium (LD) parameters were estimated from zygotic frequencies using Burrows' method. The average rate of significant LD in analysed populations of O. alpicola was about 27%. The pattern of LD over the diploid populations indicates that stochastic factors might be a primary cause of the observed multilocus associations.