Abstract
Culex bidens and C. interfor, implicated in arbovirus transmission in Argentina, are sister species, only distinguishable by feature of the male genitalia; however, intermediate specimens of the species in sympatry have been found. Fourth-instar larvae and females of both species share apomorphic features, and this lack of clear distinction creates problems for specific identification. Geometric morphometric traits of these life stages also do not distinguish the species. The aim of the present study was to assess the taxonomic status of C. bidens and C. interfor using two mitochondrial genes and to determine the degree of their reproductive isolation using microsatellite loci. Sequences of the ND4 and COI genes were concatenated in a matrix of 993 nucleotides and used for phylogenetic and distance analyses. Bayesian and maximum parsimony inferences showed a well resolved and supported topology, enclosing sequences of individuals of C. bidens (0.83 BPP, 73 BSV) and C. interfor (0.98 BPP, 97 BSV) in a strong sister relationship. The mean K2P distance within C. bidens and C. interfor was 0.3% and 0.2%, respectively, and the interspecific variation was 2.3%. Bayesian clustering also showed two distinct mitochondrial lineages. All sequenced mosquitoes were successfully identified in accordance with the best close match algorithm. The low genetic distance values obtained indicate that the species diverged quite recently. Most morphologically intermediate specimens of C. bidens from Córdoba were heterozygous for the microsatellite locus GT51; the significant heterozygote excess observed suggests incomplete reproductive isolation. However, C. bidens and C. interfor should be considered good species: the ventral arm of the phallosome of the male genitalia and the ND4 and COI sequences are diagnostic characters.
Highlights
The genus Culex L., with a worldwide distribution and 770 species grouped in 26 subgenera [1], is widely known for its medical and veterinary importance
Five haplotypes of the nicotinamide adenine dinucleotide dehydrogenase subunit 4 (ND4) fragment were found in C. bidens, and five in C. interfor, with genetic diversity indexes relatively high in both species, with Hd = 0.757 (π = 0.00326) and Hd = 0.742 (π = 0.00315), respectively
Six haplotypes of the c oxidase subunit I (COI) fragment were found in C. bidens and four in C. interfor
Summary
The genus Culex L., with a worldwide distribution and 770 species grouped in 26 subgenera [1], is widely known for its medical and veterinary importance. The subgenus exhibits polymorphic features and exceptional forms [8] and is arranged in an informal classification that includes Series, Groups, Subgroups and Complexes, with nine species without placement [1]. Morphological identification of Culex (Culex) species is difficult because anatomical traits of fourth-instar larvae and females are polymorphic and overlap among species. Morphological features of the male genitalia provide a wealth of taxonomic characters that allow reliable identification of the species, as well as synapomorphic traits that contribute to revolving phylogenetic relationships in the subgenus [9]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
