L-lactic acid: a human-signifying host cue for the anthropophilic mosquito Anopheles gambiae

Med Vet Entomol. 2002 Mar;16(1):91-8. doi: 10.1046/j.0269-283x.2002.00345.x.


Using a dual-choice olfactometer, the role of L-lactic acid was investigated in relation to host-seeking and selection by female Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) mosquitoes in a Y-tube bioassay. L-lactic acid alone was not attractive, but it significantly augmented the attractiveness of CO2, skin odour and skin-rubbing extracts from humans and other vertebrates. Comparing the left and right index fingers of the same person, one could be made more attractive than the other by adding L-lactic acid to the air stream over that finger. The difference in L-lactic acid concentration between the two air streams offered to the mosquitoes fell within the natural range of variation emanating from a human hand, suggesting that L-lactic acid modulates intraspecific host selection by An. gambiae. Analysis of skin rubbings from various vertebrates (carnivores, chickens, primates, rodents, ungulates) indicated that humans have uniquely high levels of L-lactic acid on their skin. Tests with extracts of skin rubbings from cows and humans, with and without added L-lactic acid, suggest that naturally lower levels of L-lactic acid contribute to the lesser attractiveness of non-humans to An. gambiae s.s.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anopheles / physiology*
  • Carbon Dioxide / chemistry
  • Carbon Dioxide / metabolism
  • Feeding Behavior / physiology
  • Female
  • Humans
  • Lactic Acid / chemistry*
  • Lactic Acid / metabolism
  • Odorants
  • Vertebrates / metabolism*
  • Vertebrates / parasitology


  • Carbon Dioxide
  • Lactic Acid