Posição filogenética de Lutzomyia derelicta Freitas & Barrett, 1999 (Diptera: Psychodidae: Phlebotominae)

Abstract

The classification of the subfamily Phlebotominae has been going through several changes since the early twentieth century, and even with several studies employing old and new tools, including molecular markers, doubts still remain about the relationship and differences between their representantives. These differences reflect the lack of knowledge of the true evolutionary history of the sandflies. In parallel, the old and current classifications consider mostly only adult morphological data. However, is consensus among the authors on the importance of morphological data from all life stages. These conflicts demonstrate the need for new studies to provide hypotheses that can contribute to the phylogeny of this subfamily. In this respect, Lutzomyia derelicta represents a singular sandfly because the adult forms share characteristics common to species of the New and Old World. Thus, this study aimed to provide a phylogenetic analysis with the primary purpose of determining the phylogenetic position L. derelicta in Phlebotominae, using morphological and molecular data from immature (D2 region ribosomal DNA). In the morphological analysis were analyzed 40 taxa, two from the outgroup, and 47 external characters of eggs, larvae and pupae were numerically coded as binary and Multi-State, unordered and had equal weight. The array of characters was analyzed by the programs and Winclada NINTH, using heuristic search, TBR algorithm (tree- bisection-reconnection) with 1000 replicates and ACCTRAN optimization. Phylogenetic analysis with molecular markers was performed for 22 taxa, including outgroups, and inferred by maximum likelihood (ML) using the program Treefinder, with 1000 replicates under the evolutionary model GTR + I + G determined by the software jModelTest. As a result of the morphological phylogenetic analysis, a strict consensus tree was presented with CI = 0.5 and RI = 0.75. In this analysis, the monophyletic group formed by L. derelicta, L. maruaga and L. samueli appears in a polytomy with species of Phlebotomus and another monophyletic clade formed by other species of Lutzomyia and Sergentomyia. This result suggests that L. derelicta do not belong to the subtribe Sergentomyiina as proposed by Galati (1995). These results suggest that the morphological characters of immatures stages also represent important tools for inferring phylogenetic hypotheses. Since the molecular analysis, genetic distances indicated greater similarity between L. derelicta and other species of Lutzomyia and Sergentomyia than to species of the genus Phlebotomus. Molecular phylogeny indicated that L. derelicta, L. maruaga and Edentomyia piauiensis formed a monophyletic group within the same clade where were grouped the Old World species, including species of Sergentomyia. This finding supports the hypothesis of Freitas & Barrett (1999) that L. derelicta belong to a monophyletic group, whose ancestral is vicariant of the ancestor of a group of Old World sandflies.