The current status of the Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae) species complex

Abstract

Lutzomyia longipalpis s.l. is a complex of sibling species and is the principal vector of American visceral leishmaniasis. The present review summarises the diversity of efforts that have been undertaken to elucidate the number of unnamed species in this species complex and the phylogenetic relationships among them. A wide variety of evidence, including chemical, behavioral and molecular traits, suggests very recent speciation events and complex population structure in this group. Although significant advances have been achieved to date, differential vector capacity and the correlation between structure of parasite and vector populations have yet to be elucidated. Furthermore, increased knowledge about recent epidemiological changes, such as urbanisation, is essential for pursuing effective strategies for sandfly control in the New World.

Fig. 1. : male of Lutzomyia longipalpis showing morphological variation in the tergal pale spot pattern. (A) General overview of the body; (B) one-spot phenotype; (C) intermediate phenotype; (D) two-spot phenotype. III and IV: third and fourth abdominal tergites, respectively. Bar = 1 mm.

Fig. 2. : crossing relationships between Brazilian populations of Lutzomyia longipalpis. Differential male pheromones: Cembrene-1 in green (Cemb-1), (S)-9-methyl-germacrene-B (9MGB) in red and (1S,3S,7R)-3-methyl-α-himachalene (3MαH) in blue. Variation in tergal spot pattern is shown with one and two circles representing the one- and two-spot phenotypes, respectively; two circles of unequal size represent the intermediate phenotype. Solid and dashed arrows indicate a normal and reduced insemination rate, respectively. Data modified from Ward et al. (1988) and Souza et al. (2008).

Fig. 3. : the isolation with migration model of speciation. The graphic illustrates comparisons between sympatric and allopatric Brazilian populations of Lutzomyia longipalpis using 21 nuclear loci. An ancestral population separated into two descendant groups, Pulse and Burst, at approximately 500,000 YA. The yellow arrows represent migrations between counterparts.

Fig. 4. : diagram summarising the available pheromones and copulation songs data. Differential male pheromones (blue light box): Cembrene-1 and Cembrene-2 (Cemb-1 and Cemb-2, respectively), (S)-9-methyl-germacrene-B (9MGB) and (1S,3S,7R)-3-methyl-α-himachalene (3MαH). Types and sub-types of male pheromones (black box): Burst, Pulse (subtypes P1 to P5) and Mix. The number of populations analysed is shown in brackets.