title: Occurrence of sibling species of Lutzomyia longipalpis (Diptera: Psychodidae) in Venezuela: first evidence from reproductively isolated sympatric populations.
abstract: The delimitation of cryptic species within the main vector of the American visceral leishmaniasis, Lutzomyia longipalpis, remains a topic of controversy. An analysis of genetic variability based on 8 enzymatic loci revealed fixed differences in 2 diagnostic loci, adenylate kinase (Ak) and hexokinase (Hk), between sympatric and allopatric populations at 4 localities in Venezuela. The absence of heterozygotes for these 2 loci within 1 locality indicates, for the first time, the presence of 2 sympatric reproductively isolated populations or cryptic species within L. longipalpis. Significant differences were also detected between these cryptic species in the allele frequencies of glucose-6-phosphate isomerase (Gpi) and malate dehydrogenase, decarboxylating (Me). One species showed mean heterozygosities that ranged between 6.6% and 6.7%, with 1.6-1.9 alleles detected per locus, while the other had mean heterozygosities that ranged from 4.3% to 6.3%, with 1.3-1.6 alleles per locus. Comparisons of isozyme profiles with published data suggests that 1 species is similar to the L. longipalpis described in Colombian and Brazilian populations, whereas the other has not been previously reported.
authors.affiliation: Centro de Ecología, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela.
authors.forename: M
authors.initials: M
authors.lastname: Lampo
authors.forename: D
authors.initials: D
authors.lastname: Torgerson
authors.forename: L M
authors.initials: LM
authors.lastname: Márquez
authors.forename: M
authors.initials: M
authors.lastname: Rinaldi
authors.forename: C Z
authors.initials: CZ
authors.lastname: García
authors.forename: A
authors.initials: A
authors.lastname: Arab
mesh_terms: D000483:Alleles; D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D005787:Gene Frequency; D014644:Genetic Variation; D006801:Humans; D007303:Insect Vectors / Q000145:classification / Q000201:enzymology / Q000235:genetics*; D007527:Isoenzymes / Q000235:genetics; D007898:Leishmaniasis, Visceral / Q000453:epidemiology / Q000635:transmission*; D011576:Psychodidae / Q000145:classification / Q000201:enzymology / Q000235:genetics*; D014687:Venezuela / Q000453:epidemiology
chemical_list: D007527:Isoenzymes