Variation at isoenzyme loci among males and females of Lutzomyia shannoni (Dyar) (Diptera: Psychodidae) from Colombia

Abstract

Forest populations of Lutzornyia shannoni from 3 widely separated locations in Colombia: Palarnbi (Nariño), Cimitarra (Santander) and Chinácota (Norte de Santander) were analyzed for the variation at 11 isoenzymes by sex. These samples were compared with a laboratory colony maintained at the Entomology Laboratory (INS) since 1992. The vertical electrophoresis system in 6% polyacriylamide gels was used for the analysis. The mean heterozygosity among forest females ranged from 18.5 to 24.7%, and among forest males from 13.5 to 19.4%. The mean heterozygosity in the colony females was 14.8%, whereas in males it was 20.1%, and 2.0 to 2.5 alleles were detected per locus. Nei's genetic distances among the populations were low, ranging from 0.005 to 0.073. In the colony sample of 79 individuals, the Gpi locus was homozygous in all females and heterozygous in all males. Although this is probably a consequence of colonization, it indicates that Gpi locus is tightly linked to the sex determining mechanism, with the Gpi0,62 allele on the female locus and the Gpi0,72 allele associated with the male locus.