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

Abstract

Abstract. 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 (Ͻ 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.

Phylogeography of the neotropical sand fly Lutzomyia longipalpis inferred from mitochondrial DNA sequences

“…We describe these as follows: species A (Laran Clade), species B (Brazilian Clade), species C (cis-Andean Clade) and species D (trans-Andean Clade). These results are consistent with earlier studies based on isozyme analysis (Lanzaro et al, 1993Mutebi et al, 1998Mutebi et al, , 1999Lampo et al, 1999).…”

“…Phylogenetic analysis (MP) reveals close relationships among populations in the Brazilian highlands (Lapinha Cave), the Amazon (Salvaterra and Santarem), San Francisco Basin (Jacobina) and Brazilian scrubland (Baturité). These results are concordant with patterns of divergence in the nuclear genome (isozyme variation) among the same Brazilian populations, with the exception of the population at Roraima, that was not included in the isozyme studies (Mukhopadhyay et al, 1998;Mutebi et al, 1999;Azevedo et al, 2000). These authors concluded that populations in Brazil represent a single species, but with relatively high levels of genetic divergence among local populations.…”

“…1). Populations were selected based on previous isozyme studies that suggested these populations represent three or more species (Lanzaro et al, 1993;Mutebi et al, 1998Mutebi et al, , 1999Yin et al, 1998;Arrivillaga et al, 2000, in press). Adult flies were collected in Colombia, Costa Rica, Brazil, Honduras and Venezuela using aspirators from domestic animals (chickens, cattle, pigs or dogs) or from resting sites near animal enclosures, and with Centers for Disease Control (CDC, Atlanta, USA) light traps.…”

Courtship song genes and speciation in sand flies

“…The calculated Fst for the data is 0.3911 (Hudson et al 1992, Rozas & Rozas 1999). This figure predicts only 0.39 migrants per generation (Nm), a value nearly ten times smaller than the ones predicted by isoenzyme loci (Mukhopadhyay et al 1998, Mutebi et al 1999, Azevedo et al 2000.…”

Lutzomyia longipalpis and the eco-epidemiology of American visceral leishmaniasis, with particular reference to Brazil: a review

“…The existence of such cryptic species in Brazil was disputed by Mukhopadhyay et al (1998), Mutebi et al (1999), Azevedo et al (2000), and Arrivillaga et al (2002Arrivillaga et al ( , 2003 who considered that there is only a single species in that country, based on a study of several widely separated populations for genetic variability in biochemical characters. They felt that the reasons for any epidemiological variations in AVL should be sought elsewhere.…”