Breeding structure of the sand fly Lutzomyia longipalpis (Lutz & Neiva) in Brazil

• Published in: The American journal of tropical medicine and hygiene Vol. 61; no. 1; pp. 149 - 157
• Main Authors: Mutebi, JP, Alexander, B, Sherlock, I, Wellington, J, Souza, AA, Shaw, J, Rangel, EF, Lanzaro, GC
• Format: Journal Article
• Language: English
• Published: Lawrence, KS ASTMH 01.07.1999; Allen Press
• Subjects: Alleles; Animals; Biological and medical sciences; Brazil; Electrophoresis, Starch Gel; Female; Fundamental and applied biological sciences. Psychology; Genetic Variation - genetics; Humans; Insect Vectors - enzymology; Insect Vectors - genetics; Leishmania - chemistry; Leishmania chagasi; Leishmaniasis, Visceral - transmission; Lutzomyia longipalpis; Male; Medically important nuisances and vectors, pests of stored products and materials: population survey and control; Phylogeny; Psychodidae; Psychodidae - enzymology; Psychodidae - genetics; Tropical medicine; Vectors. Intermediate hosts; South America; Brazil; America; Kinetoplastida; Protozoa; Protozoal disease; Genetic variability; Insecta; Psychodidae; Kala azar; Leishmaniasis; Parasitosis; Infection; Leishmania chagasi; Arthropoda; Genetics; Invertebrata; Structure; Vector; Diptera; Lutzomyia longipalpis
• ISSN: 0002-9637; 1476-1645
• DOI: 10.4269/ajtmh.1999.61.149

Eleven populations of Lutzomyia longipalpis (Lutz & Neiva), the sand fly vector of Leishmania chagasi, from different areas of Brazil were analyzed for genetic variation at 16 enzyme loci. In this region, the prevalence of visceral leishmaniasis (VL) caused by L. chagasi is spotty and reproductive isolation among populations of Lu. longipalpis has been reported. It is thought that morphologically similar cryptic species with varying vectorial capacity may be responsible for the discontinuous distribution of VL. The aim was to study the genetic structure of populations within this region and to identify demes that may represent sibling species. Genotypic frequencies within populations were in close compliance to Hardy-Weinberg expectations, suggesting there are no sympatric species among these 11 populations. Levels of genetic distance between pairs of populations were very low (< 0.03), consistent with local populations within a single sand fly species. When genotypic frequency data for all populations were pooled, 9 of the 13 polymorphic loci deviated from Hardy-Weinberg expectations, indicating some degree of genetic substructuring. Estimates of effective migration rates (N(e)m) among all populations were low, 2.73, suggesting that gene flow is restricted among populations, which is probably the reason for the observed genetic substructuring.