A preliminary isoenzyme study on five species of phlebotomine sandflies in China

During June to August, 1987, six species of phlebotomines were collected by aspirator from four localities in Beijing, Nanjiang and northwestern Sichuan Province. After morphological identification, five species viz., Phlebotomus chinensis, P. sichuanensis, Sergentomyia zhengjiani, S. khawi and S. squamirostris were studied starch gel electrophoresis in 10 enzymes for isoenzyme characterization. Among which four enzymes (MDH, PGM, PGI and alpha-GPD) showed varying degrees of differences. The characteristic enzyme locus of PGM can be used to identify P. sichuanensis (Sichuan strain) from P. chinensis (Sichuan and Beijing strains) two vectors of Chinese visceral leishmaniasis, the pharyngeal armatures and spermathecae of which are morphologically resemble in females. The locus of PGM for genotype AA is over 77% in P. chinensis compared with 8.3% in P. sichuanensis and genotype DD is 75% in P. sichuanensis compared with negative in P. chinensis. Distinct enzymatic differences were demonstrated between genera Phlebotomus and Sergentomyia. The alleles of MDH-1 were 100 and 95 in genus Phlebotomus and Sergentomyia respectively, meanwhile in alpha-GPD the alleles were at 100 and 97 respectively except S. squamirostris. In PGI it showed polymorphic with two loci and more alleles in Phlebotomus and monomorphic with only one locus in Sergentomyia. The similar enzyme phenotype between morphologically distinct species, S. zhengjiani and S. khawi shown that the uncorrespondence between morphological and genetic characters in evolution is present in some cases of phlebotomine such as in other insects.