Infection, Genetics and Evolution 2 (2002) 83–95 Phylogeography of the neotropical sand fly Lutzomyia longipalpis inferred from mitochondrial DNA sequences J.C. Arrivillaga a,b , D.E. Norris c , M.D. Feliciangeli b , G.C. Lanzaro a,∗ a Department of Pathology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-0609, USA b Universidad De Carabobo, Fac, de Ciencias de la Salud, BIOMED, Centro Nacional de Referencia de Flebotomos, La Morita, Maracay, Apdo. 4873, Venezuela c The W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA Received 8 October 2001; received in revised form 14 May 2002; accepted 8 June 2002 Abstract Sand flies in the Lutzomyia longipalpis species complex include the primary vector of Leishmania chagasi, the etiologic agent of visceral leishmaniasis in the Neotropics. Twelve L. longipalpis populations from South and Central America were compared using the cytochrome c oxidase I (COI) gene from the mitochondrial genome. The haplotype profiles for each population revealed that the majority of sequence variation was inter-population (98%) rather than intra-population, suggesting that sequence polymorphisms at the COI locus should provide excellent characters for the study of phylogenetic relationships among populations. Phylogenetic reconstruction using distance (neighbor-joining) and maximum parsimony analysis revealed the existence of four clades among the L. longipalpis populations studied: (1) Laran, (2) Brazilian, (3) cis-Andean and (4) trans-Andean. We suggest that these clades represent species. A biogeographical interpretation of the molecular phylogeny suggests that the process of speciation in the L. longipalpis complex began in the Pliocene, from a sub-Andean–Amazonian gene pool resulting from the Andean orogeny (formation of the East Andean Cordillera). The four clades probably diverged as a result of vicariance events that occurred throughout the late Pliocene and Pleistocene. We propose and discuss several historical scenarios, based on the biogeography and historical geology of Central and South America. © 2002 Elsevier Science B.V. All rights reserved. Keywords: Lutzomyia longipalpis; mtDNA; Phylogeny; Sand flies; Vicariance 1. Introduction Lutzomyia longipalpis (Diptera: Psychodidae), the prin- cipal vector of visceral leishmaniasis in the Neotropics, was first described from collections made in Brazil by Lutz & Neiva in 1912. Reviews by Forattini (1973) and Young and Duncan (1994) report L. longipalpis as a Neotropical species with a broad distribution from southern Mexico to northern Argentina. Although widespread, its geographic distribution is discontinuous. Its geographic range includes climatic and physiogeographic discontinuities that are as- sociated with patterns of population divergence. There is now a consensus that L. longipalpis is a complex of sibling species distinguishable on the basis of male pheromone composition (Ward et al., 1988; Hamilton et al., 1996a,b,c), allozyme frequencies (Lanzaro et al., 1993; Arrivillaga, ∗ Corresponding author. Present Address: Department of Entomology, University of California, Davis, CA 95616, USA. Fax: +1-409-747-2437. E-mail address: glanzaro@utmb.edu (G.C. Lanzaro). 1999; Lampo et al., 1999), interspecific male hybrid steril- ity (Lanzaro et al., 1993), chromosome patterns (Yin et al., 1998) and larval morphology (Arrivillaga et al., 2000, in press). However, the number of species within the com- plex and their geographic distributions remain unclear. Little is known about phylogenetic relationships among L. longipalpis populations. This knowledge is necessary for the development of models that will provide a better understanding of the current geographic distributions and processes of speciation for members of this complex. In addition, an improved understanding of the biogeography and genetics of these populations may help clarify their taxonomic status. Mitochondrial DNA (mtDNA) has proven useful in molecular phylogenetics due to its maternal inheritance, rapid rate of divergence and lack of recombination (Avise et al., 1987; Avise, 1994; Moritz, 1994; Simon et al., 1994). Little is known about the molecular genetics of this group of sand flies (Esseghir et al., 1997; Ready et al., 1997, 1998; Ishikawa et al., 1999). However, studies of the 1567-1348/02/$ – see front matter © 2002 Elsevier Science B.V. All rights reserved. PII:S1567-1348(02)00087-4