title: Taxis assays measure directional movement of mosquitoes to olfactory cues.
abstract: BACKGROUND
  Malaria control methods targeting indoor-biting mosquitoes have limited impact on vectors that feed and rest outdoors. Exploiting mosquito olfactory behaviour to reduce blood-feeding outdoors might be a sustainable approach to complement existing control strategies. Methodologies that can objectively quantify responses to odour under realistic field conditions and allow high-throughput screening of many compounds are required for development of effective odour-based control strategies.
  
  
  METHODS
  The olfactory responses of laboratory-reared Anopheles gambiae in a semi-field tunnel and A. arabiensis females in an outdoor field setting to three stimuli, namely whole human odour, a synthetic blend of carboxylic acids plus carbon dioxide and CO(2) alone at four distances up to 100 metres were measured in two experiments using three-chambered taxis boxes that allow mosquito responses to natural or experimentally-introduced odour cues to be quantified.
  
  
  RESULTS
  Taxis box assays could detect both activation of flight and directional mosquito movement. Significantly more (6-18%) A. arabiensis mosquitoes were attracted to natural human odour in the field up to 30 metres compared to controls, and blended synthetic human odours attracted 20% more A. gambiae in the semi-field tunnel up to 70 metres. Whereas CO(2) elicited no response in A. arabiensis in the open field, it was attractive to A. gambiae up to 50 metres (65% attraction compared to 36% in controls).
  
  
  CONCLUSIONS
  We have developed a simple reproducible system to allow for the comparison of compounds that are active over medium- to long-ranges in semi-field or full-field environments. Knowing the natural range of attraction of anopheline mosquitoes to potential blood sources has substantial implications for the design of malaria control strategies, and adds to the understanding of olfactory behaviour in mosquitoes. This experimental strategy could also be extended from malaria vectors to other motile arthropods of medical, veterinary and agricultural significance.
authors: Disease Control Department, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. lena.m.lorenz@gmail.com
authors: Lena M
authors: LM
authors: Lorenz
authors: Aidan
authors: A
authors: Keane
authors: Jason D
authors: JD
authors: Moore
authors: Cristina J
authors: CJ
authors: Munk
authors: Laura
authors: L
authors: Seeholzer
authors: Antony
authors: A
authors: Mseka
authors: Emmanuel
authors: E
authors: Simfukwe
authors: Joseph
authors: J
authors: Ligamba
authors: Elizabeth L
authors: EL
authors: Turner
authors: Lubandwa R
authors: LR
authors: Biswaro
authors: Fredros O
authors: FO
authors: Okumu
authors: Gerry F
authors: GF
authors: Killeen
authors: Wolfgang R
authors: WR
authors: Mukabana
authors: Sarah J
authors: SJ
authors: Moore
mesh_terms: D000818:Animals; D000852:Anopheles / Q000187:drug effects* / Q000502:physiology*; D001522:Behavior, Animal / Q000187:drug effects*; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D004772:Entomology / Q000379:methods*; D005260:Female; D008124:Locomotion; D010675:Pheromones / Q000494:pharmacology*; D012903:Smell / Q000187:drug effects
chemical_list: D010675:Pheromones; C010411:insect attractants
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