title: The range of attraction for light traps catching Culicoides biting midges (Diptera: Ceratopogonidae).
abstract: BACKGROUND
  Culicoides are vectors of e.g. bluetongue virus and Schmallenberg virus in northern Europe. Light trapping is an important tool for detecting the presence and quantifying the abundance of vectors in the field. Until now, few studies have investigated the range of attraction of light traps.
  
  
  METHODS
  Here we test a previously described mathematical model (Model I) and two novel models for the attraction of vectors to light traps (Model II and III). In Model I, Culicoides fly to the nearest trap from within a fixed range of attraction. In Model II Culicoides fly towards areas with greater light intensity, and in Model III Culicoides evaluate light sources in the field of view and fly towards the strongest. Model II and III incorporated the directionally dependent light field created around light traps with fluorescent light tubes. All three models were fitted to light trap collections obtained from two novel experimental setups in the field where traps were placed in different configurations.
  
  
  RESULTS
  Results showed that overlapping ranges of attraction of neighboring traps extended the shared range of attraction. Model I did not fit data from any of the experimental setups. Model II could only fit data from one of the setups, while Model III fitted data from both experimental setups.
  
  
  CONCLUSIONS
  The model with the best fit, Model III, indicates that Culicoides continuously evaluate the light source direction and intensity. The maximum range of attraction of a single 4W CDC light trap was estimated to be approximately 15.25 meters. The attraction towards light traps is different from the attraction to host animals and thus light trap catches may not represent the vector species and numbers attracted to hosts.
authors.affiliation: National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, Frederiksberg C, DK-1870, Denmark. ckir@vet.dtu.dk
authors.forename: Carsten
authors.initials: C
authors.lastname: Kirkeby
authors.forename: Kaare
authors.initials: K
authors.lastname: Græsbøll
authors.forename: Anders
authors.initials: A
authors.lastname: Stockmarr
authors.forename: Lasse E
authors.initials: LE
authors.lastname: Christiansen
authors.forename: René
authors.initials: R
authors.lastname: Bødker
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D001819:Bluetongue / Q000635:transmission; D002044:Bunyaviridae Infections / Q000635:transmission / Q000662:veterinary; D002417:Cattle; D002519:Ceratopogonidae / Q000502:physiology* / Q000528:radiation effects / Q000821:virology; D003718:Denmark; D004784:Environmental Monitoring; D006801:Humans; D007303:Insect Vectors / Q000502:physiology* / Q000528:radiation effects / Q000821:virology; D008027:Light; D008954:Models, Biological; D016851:Orthobunyavirus / Q000502:physiology