Developmental Characteristics, Genetic Compatibility and Esterase Zymograms in Three Strains of the Hawthorn Spider Mite, Tetranychus viennensis Zacher (Acari: Tetranychidae).

Abstract

Developmental success on 55 species of plant, traits of population growth, reproductive compatibility and esterase zymograms were studied for three strains of the hawthorn spider mite, Tetranychus viennensis Zacher, collected from apple, cherry and deciduous oak trees, respectively. The host ranges for the apple and cherry strains of mites were similar, but were different from the host range for the deciduous oak strain. The intrinsic rates of natural increase(rm)for the apple and deciduous oak strains were similar, but slightly lower than the value for the cherry strain, showing no clear difference in rm between the two rosaceous strains and the deciduous oak strain. Each strain produced both female and male progeny.Inter-strain crosses between the apple and cherry strains also produced both sexes, but either of these strains produced only male progeny when paired with the deciduous oak strain, suggesting that the former were reproductively incompatible with the deciduous oak strain.Among the8esterase bands detected in mites, one(E7)was common for all the three strains, and another band(E1)appeared only in the cherry strain. Three other bands were exclusively found in both the apple and cherry strains. The rest were found only in the deciduous oak strain. These results clearly suggest that the apple and cherry strains on rosaceous trees constitute one species while the deciduous oak strain from fagaceous trees belongs to another.