ELECTROANTENNOGRAM RESPONSES OF THE STABLE FLY, STOMOXYS-CALCITRANS, TO COMPONENTS OF HOST ODOR

Electroantennograms (EAGs) were recorded from laboratory-reared male and female Stomoxys calcitrans (L.) in response to a range of synthetic chemicals known to be electrophysiologically-active for other biting flies. Of the eight compounds initially tested, only two -1-octen-3-ol and 3-methylphenol - consistently elicited larger electroantennograms (EAGs) than did control treatments; 1-octen-3-ol was the most potent. EAG recovery time was inversely correlated with EAG amplitude. EAGs recorded with primary C-2-C-12 carbon chain-length primary aliphatic alcohols peaked at octan-1-ol with pentan-1-ol, hexan-1-ol and heptan-1-ol also eliciting EAG responses significantly larger than the controls. When different C-8 carbon chain compounds and nonane were tested: 1-octen-3-ol elicited the largest EAGs followed by, in decreasing activity, octan-1-ol, 1-bromooctane, octan-3-ol, octanal, 2-octanone, octanoic acid and nonane. The EAG response of 1-octen-3-ol increased sigmoidally with dose, with the threshold at between 2 and 20 ng, and the peak response at 200 mu g on filter paper. EAGs larger than control were also elicited by entrained ox odour and ox breath. The behavioural implications are discussed.