Landing responses of Anopheles gambiae elicited by oxocarboxylic acids.
A wind tunnel bioassay and video system were used to observe Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) landing on glass cylinders, heated to human skin temperature (34 degrees C) and treated with aqueous solutions of oxocarboxylic acids. Six of nine compounds tested: 2-oxobutanoic, 2-oxo-3-methylbutanoic, 2-oxopentanoic, 2-oxo-3-methylpentanoic, 2-oxo-4-methylpentanoic and 2-oxohexanoic elicited significant landing responses in comparison to a water control. Landing responses appeared to be restricted to C4-C6, 2-oxocarboxylic acids. A solution of 1 microg/microL of 2-oxopentanoic acid elicited the highest level of response that was temperature dependent: significant numbers of landings occurred only within +/-2 degrees C of human skin temperature. Chemical analysis by linked gas-liquid chromatography/mass spectrometry of methyl-oxime, trimethylsilyl derivatized samples of human sweat extracts revealed the presence of 2-oxopropanoic (pyruvic) acid and three behaviourally active, branched chain acids: 2-oxo-3-methylbutanoic, 2-oxo-3-methylpentanoic and 2-oxo-4-methylpentanoic.
Imperial College at Wye, University of London, Ashford, Kent, UK. t.healy@ic.ac.uk
T P
TP
Healy
M J W
MJ
Copland
A
A
Cork
A
A
Przyborowska
J M
JM
Halket
D000818:Animals; D000852:Anopheles / Q000502:physiology*; D001522:Behavior, Animal / Q000187:drug effects; D001681:Biological Assay; D002264:Carboxylic Acids / Q000032:analysis / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005426:Flight, Animal; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D010421:Pentanoic Acids / Q000032:analysis*; D013329:Structure-Activity Relationship; D013542:Sweat / Q000737:chemistry*; D013696:Temperature; D014741:Video Recording
D002264:Carboxylic Acids; D010421:Pentanoic Acids