title: Mosquito host preferences affect their response to synthetic and natural odour blends.
abstract: BACKGROUND
  The anthropophilic malaria mosquito Anopheles gambiae sensu stricto (hereafter termed Anopheles gambiae) primarily takes blood meals from humans, whereas its close sibling Anopheles arabiensis is more opportunistic. Previous studies have identified several compounds that play a critical role in the odour-mediated behaviour of An. gambiae. This study determined the effect of natural and synthetic odour blends on mosquitoes with different host preferences to better understand the host-seeking behaviour of mosquitoes and the potential of synthetic odour blends for standardized monitoring.
  
  
  METHODS
  Odour blends were initially tested for their attractiveness to An. gambiae and An. arabiensis in a semi-field system with MM-X traps baited with natural and synthetic odours. Natural host odours were collected from humans, cows and chickens. The synthetic odour blends consisted of three or five previously identified compounds released with carbon dioxide. These studies were continued under natural conditions where odour blends were tested outdoors to determine their effect on species with different host preferences.
  
  
  RESULTS
  In the semi-field experiments, human odour attracted significantly higher numbers of both mosquito species. However, An. arabiensis was also attracted to cow and chicken odours, which confirms its opportunistic behaviour. A five-component synthetic blend was highly attractive to both mosquito species. In the field, the synthetic odour blend caught significantly more An. funestus than traps baited with human odour, while no difference was found for An. arabiensis. Catches of An. arabiensis and Culex spp. contained large numbers of blood-fed mosquitoes, mostly from cows, which indicates that these mosquitoes had fed outdoors.
  
  
  CONCLUSIONS
  Different odour baits elicit varying responses among mosquito species. Synthetic odour blends are highly effective for trapping mosquitoes; however, not all mosquitoes respond equally to the same odour blend. Combining fermenting molasses with synthetic blends in a trap represents the most effective tool to catch blood-fed mosquitoes outside houses, which is essential for understanding outdoor malaria transmission.
authors.affiliation: International Centre of Insect Physiology and Ecology, PO Box 30772-00100 GPO, Nairobi, Kenya. obukosia@yahoo.com.|Laboratory of Entomology, Wageningen University, PO Box 8031, 6700 EH, Wageningen, The Netherlands. obukosia@yahoo.com.
authors.forename: Annette O
authors.initials: AO
authors.lastname: Busula
authors.affiliation: Laboratory of Entomology, Wageningen University, PO Box 8031, 6700 EH, Wageningen, The Netherlands. willem.takken@wur.nl.
authors.forename: Willem
authors.initials: W
authors.lastname: Takken
authors.affiliation: Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, 3610 Hamilton Walk, Philadelphia, PA, 19104-6076, USA. eloy@mail.med.upenn.edu.
authors.forename: Dorothy E
authors.initials: DE
authors.lastname: Loy
authors.affiliation: Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, 3610 Hamilton Walk, Philadelphia, PA, 19104-6076, USA. bhahn@mail.med.upenn.edu.
authors.forename: Beatrice H
authors.initials: BH
authors.lastname: Hahn
authors.affiliation: International Centre of Insect Physiology and Ecology, PO Box 30772-00100 GPO, Nairobi, Kenya. rmukabana@yahoo.co.uk.|School of Biological Sciences, University of Nairobi, PO Box 30197-00100 GPO, Nairobi, Kenya. rmukabana@yahoo.co.uk.
authors.forename: Wolfgang R
authors.initials: WR
authors.lastname: Mukabana
authors.affiliation: Laboratory of Entomology, Wageningen University, PO Box 8031, 6700 EH, Wageningen, The Netherlands. niels.verhulst@wur.nl.
authors.forename: Niels O
authors.initials: NO
authors.lastname: Verhulst
mesh_terms: D000818:Animals; D000852:Anopheles / Q000187:drug effects* / Q000502:physiology*; D002417:Cattle; D002645:Chickens; D003465:Culex / Q000187:drug effects* / Q000502:physiology*; D005247:Feeding Behavior / Q000187:drug effects; D005260:Female; D058507:Host Specificity; D006801:Humans; D008297:Male; D009812:Odorants; D010675:Pheromones / Q000378:metabolism*
chemical_list: D010675:Pheromones; C010411:insect attractants