CUTICULAR HYDROCARBON COMPOSITION AND PHENOTYPIC VARIABILITY IN SYMPATRIC POPULATIONS OF IXODES-RICINUS TICKS FROM POLAND

Gas chromatography of cuticular hydrocarbons was used to assess geneti c similarity and heterozygosity between 18 sympatric populations of ad ult Ixodes ricinus ticks collected from Poland. Sixteen n-alkanes, 45 monomethylalkanes, and 36 dimethylalkanes were identified. Forty-one c ompounds were detected in 90% of the specimens and nine hydrocarbons w ere present in all the specimens studied. Visual inspection of chromat ograms revealed major differences in the relative abundance of hydroca rbons between populations of I. ricinus. The average proportion of het erozygotic hydrocarbons was 50.68%, while the average genetic similari ty among all populations was 0.967. Two other methods were used to mea sure the intrapopulation variability: the number of isomeric forms for each hydrocarbon and the range of hydrocarbon abundance. It was found that some hydrocarbons manifested an unexpectedly high number of isom eric patterns, such as nonacosane (21 patterns), triacontane (23), pen tacosane (26), and hexacosane (28). Our data suggest that I. ricinus t icks from Poland consist of several interbreeding, non-isolated popula tions, with a high degree of genetic flow between them.