Electrophoretically detectable protein variation in natural populations of the lone star tick, Amblyomma americanum (Acari: Ixodidae)

Abstract

Nine populations of Amblyomma americanum (L.) were examined electrophoretically for variation of 21 enzymes. Only three enzymes were not polymorphic and the average heterozygosity per individual (h) for the species was 0085 with a range of 0077 to 0110, comparing well with values in other arthropods. The average Nei identity value for pairwise comparisons among the nine populations was high, 0994 0004 (ISD). These high identity values and the absence of geographic structuring of the protein variation suggest that this species is genetically homogeneous. Normal levels of genie variability within and a lack of divergence between populations were not predicted by models developed to describe these genetic characteristics on the basis of the heterogeneities encountered by parasites in their environment. An analysis of data from several different species of ticks suggests host mobility and abundance, as well as tick abundance and selectivity in choosing a host, are important parameters in determining genetic variation in these ectoparasites.