Comparative morphological and molecular analysis confirms the presence of the West Nile virus mosquito vector, Culex univittatus, in the Iberian Peninsula

Abstract

Background Culex univittatus and Culex perexiguus mosquitoes (Diptera: Culicidae) are competent arbovirus vectors, but with unclear morphological differentiation. In Europe, and in the Iberian Peninsula in particular, the presence of either or both species is controversial. However, in order to conduct adequate surveillance for arboviruses in this region, it is crucial to clarify whether Cx. univittatus is present or not, as well as to critically assess existing differentiation tools. This study aimed to clarify this situation, by morphological and molecular phylogenetic comparison of Iberian specimens deemed as Cx. univittatus, with others of South African origin, i.e. from the type-locality region.MethodsThus, morphological characteristics useful to distinguish both species, such as midfemur pale line, hindfemur R ratio, seta g R1 ratio, seta f shape, length of ventral arm of phalosome and number of setae on IX tergal abdominal segment, were observed. A phylogenetic analysis based on cox1 mtDNA, of which there were no sequences from Cx. univittatus yet available in the GenBank database, was performed.ResultsThis analysis showed that Iberian and South African specimens are morphologically similar, except for the length of the ventral arm of the phalosome, which was higher in the Iberian specimens. Although the Iberian specimens could not be accurately identified using BOLD Systems, phylogenetic analysis still grouped these closer to South African Cx. univittatus, than to Cx. perexiguus from Turkey and Pakistan, despite the observed segregation of both taxa as two individual monophyletic clusters with shared common ancestry.ConclusionsThis survey demonstrates that the West Nile virus vector Cx. univittatus is present in the Iberian Peninsula.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1877-7) contains supplementary material, which is available to authorized users.

The mosquito fauna of the western region of Spain with emphasis on ecological factors and the characterization ofCulex pipiensforms

“…pipiens s.s. by CQ11FL assays, pipiens form and molestus form were detected. The presence of Culex univittatus was confirmed in another study (Mixão et al ).…”

An appetite for pests: Synanthropic insectivorous bats exploit cotton pest irruptions and consume various deleterious arthropods

“…We found additional prey associated with human habitats, such as mosquitos from the genus Culex (e.g., Culex perexiguus) that can carry diseases like the West Nile virus (Mixão et al, 2016;Robinson, 2005), as well as drain flies (e.g., Psychoda alternata) and midges (e.g., Kiefferulus brevibucca) that are considered nuisance pests when their populations are overabundant in residential areas (Robinson, 2005). Thus, it seems the potential of P. kuhlii as a predator and the TA B L E 1 Prey of human concern detected in the diet of Pipistrellus kuhlii using DNA metabarcoding of faecal samples (n = 132) from Emek-Hefer, Israel Table S3.…”

First confirmed occurrence of the yellow fever virus and dengue virus vector Aedes (Stegomyia) luteocephalus (Newstead, 1907) in Mozambique

“…Preliminary analysis of the nucleotide sequences of cox 1 mtDNA obtained from the 4 males revealed completely identical sequences, which suggests that the Ae . luteocephalus larvae sequenced were siblings [ 28 ], possibly hatched from eggs laid by a single female, as mtDNA is maternally inherited, quite possible given the small dimensions of the breeding rock pool (Additional file 1 : Figure S1).…”

“…All samples collected were then transported to local insectaries for rearing to adults [25,26]. Preliminary morphological identification was conducted on adult stages emerged, using taxonomic keys [15,21,[27][28][29]. Adult specimens were preserved individually in single 1.5 ml Eppendorf tubes at − 80 °C for further morphological and molecular analysis.…”

“…luteocephalus were re-observed and male terminalia were separated from the abdomen and adsorbed in Marc André solution [27]. Genitalia were dissected under stereomicroscope and mounted in formic acid-polyvinyl alcohol (PVA) solution between a slide and a cover slip [27,28] and photographed under Olympus stereomicroscope SZ51 (Olympus, Seoul, South Korea), Olympus microscope (BX51, Olympus, Seoul, South Korea) and an Olympus SC30 digital camera (Olympus, Tokyo, Japan), respectively.…”