title: Ecological characterization and molecular differentiation of Culex pipiens complex taxa and Culex torrentium in eastern Austria.
abstract: BACKGROUND
  Culex pipiens complex taxa differ in behaviour, ecophysiology and epidemiologic importance. Despite their epidemiologic significance, information on genetic diversity, occurrence and seasonal and spatial distribution patterns of the Cx. pipiens complex is still insufficient. Assessment of seasonal and spatial distribution patterns of Culex pipiens forms and their congener Cx. torrentium is crucial for the understanding of their vector-pathogen dynamics.
  
  
  METHODS
  Female mosquitoes were trapped from April-October 2014 twice a month for a 24-h time period with BG-sentinel traps at 24 sampling sites in eastern Austria, using carbon dioxide as attractant. Ecological forms of Cx. pipiens s.l. and their hybrids were differentiated using the CQ11 locus, and Cx. pipiens forms and their congener Cx. torrentium using the ACE-2 gene. Differential exploitation of ecological niches by Cx. pipiens forms and Cx. torrentium was analysed using likelihood ratio tests. Possible effects of environmental parameters on these taxa were tested using PERMANOVA based on distance matrices and, if significant, were modelled in nMDS ordination space to estimate non-linear relationships.
  
  
  RESULTS
  For this study, 1476 Culex spp. were sampled. Culex pipiens f. pipiens representing 87.33 % of the total catch was most abundant, followed by hybrids of both forms (5.62 %), Cx. torrentium (3.79 %) and Cx. pipiens f. molestus (3.25 %). Differences in proportional abundances were found between land cover classes. Ecological parameters affecting seasonal and spatial distribution of these taxa in eastern Austria are precipitation duration, air temperature, sunlight and the interaction term of precipitation amount and the Danube water level, which can be interpreted as a proxy for breeding habitat availability.
  
  
  CONCLUSIONS
  The Cx. pipiens complex of eastern Austria comprises both ecologically different forms, the mainly ornithophilic form pipiens and the mainly mammalophilic and anthropophilic form molestus. Heterogeneous agricultural areas as areas of coexistence may serve as hybridization zones, resulting in potential bridge vectors between birds and humans. Occurrence, seasonal and spatial distribution patterns of the Cx. pipiens complex and Cx. torrentium and the presence of hybrids between both forms were quantified for the first time in Austria. These findings will improve the knowledge of their vector-pathogen dynamics in this country.
authors.affiliation: Department of Pathobiology, Institute of Parasitology, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: Carina
authors.initials: C
authors.lastname: Zittra
authors.affiliation: Department of Pathobiology, Institute of Parasitology, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: Eva
authors.initials: E
authors.lastname: Flechl
authors.affiliation: Department of Pathobiology, Institute of Parasitology, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Kothmayer
authors.affiliation: Department of Limnology and Bio-Oceanography, University of Vienna, Vienna, Austria.
authors.forename: Simon
authors.initials: S
authors.lastname: Vitecek
authors.affiliation: , Donaustraße 73, 3421, Höflein/Donau, Austria.
authors.forename: Heidemarie
authors.initials: H
authors.lastname: Rossiter
authors.affiliation: Biological Station Lake Neusiedl, Illmitz, Burgenland, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Zechmeister
authors.affiliation: Department of Pathobiology, Institute of Parasitology, University of Veterinary Medicine Vienna, Vienna, Austria. hans-peter.fuehrer@vetmeduni.ac.at.
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Fuehrer
mesh_terms: D000818:Animals; D001317:Austria; D058448:Biota; D003465:Culex / Q000145:classification* / Q000235:genetics / Q000254:growth & development*; D005260:Female; D014644:Genetic Variation; D012621:Seasons; D017422:Sequence Analysis, DNA; D062211:Spatio-Temporal Analysis
keywords: Acetylcholinesterase (ACE gene); Autecology; CQ11; Diversity; Mosquito; Vector