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L ‐lactic acid: a human‐signifying host cue for the anthropophilic mosquito Anopheles gambiae
Author(s) -
Dekker T.,
Steib B.,
Cardé R. T.,
Geier M.
Publication year - 2002
Publication title -
medical and veterinary entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 82
eISSN - 1365-2915
pISSN - 0269-283X
DOI - 10.1046/j.0269-283x.2002.00345.x
Subject(s) - olfactometer , biology , lactic acid , anopheles gambiae , host (biology) , zoology , botany , food science , ecology , bacteria , genetics , malaria , immunology
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 CO 2 , 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.