Recording of electroantennographic (EAG) responses from tsetse, Glossina pallidipes and G. morsitans morsitans (Diptera: Glossinidae) has been used to detect olfactory stimulants in volatiles from cattle. The most potent stimulant in cattle odours collected on Porapak resin has been identified as 1-octen-3-ol by gas chromatographic retention data and mass spectrometry. The rate of production of l-octen-3-ol by a normal ox was estimated to be 0.043 mghr" 1 , and the natural material was shown to be predominantly the (/?)-( -)enantiomer. No l-octen-3-ol was collected under the conditions used in the absence of an ox. EAG dose-response curves to l-octen-3-ol showed it to be about 10 6 times more potent than acetone, a known attractant for tsetse, with the maximum response of about 1 mV occurring to approx. 1 ng at source. l-Octen-3-ol caused increased upwind flight by tsetse in a wind tunnel bioassay, and in the field it was attractive to tsetse by itself and also increased the attractiveness of both ox odour and of mixtures of carbon dioxide and acetone.Resume-Les reponses electroantennographique (EAG) des mouches tse-tse, Glossina pallidipes et G. morsitans morsitans (Diptera: Glossinidae), ont ete notees afin de decouvrir les stimulants olfactifs parmi les composes volatils emanant du betail. Le stimulant le plus puissant dans l'odeur de betail, recueillie sur la resine Porapak, a ete identifie comme l-octen-3-ol en utilisant des donnees de retention chromatographique en phase gazeuse et spectrometrie de mass. On a estime le taux de production de l-octen-3-ol par un boeuf normal a 0,043 mghr" 1 et la matiere naturelle s'est revelee comme composee en majeure partie de l'enantiomere (R)- (-). Dans les conditions utilisees, on n'a recueillie de l-octen-3-ol qu'en presence d'un boeuf. Les courbes de dosage-reponse EAG pour l-octen-3-ol l'a revele a peu pres 10 6 fois plus puissant que l'acetone, un attractant connu pour les mouches tse-tse, la reponse maximum d'environ 1 mV etant enregistree pour environ 1 ng a la source. l-Octen-3-ol a occasionne un accroissement de vol des mouches tse-tse contre le vent dans un tunnel aerodynamique. Sur le terrain l-octen-3-ol s'est reveje attractif tout seul et a augmente la puissance attractive de l'odeur de boeuf et aussi des melanges de bioxyde de carbone et d'acetone.

The attractiveness of cattle urine to Glossina morsitans morsitans Westwood and G. pallidipes Austen was shown to be entirely attributable to the phenolic components which it contains. Four of the eight naturally occurring phenol derivatives (3- and 4-methylphenol, 3-ethylphenol and 3-n-propylphenol) were electroantennographically active, induced upwind flight in wind-tunnel bioassays and increased trap catches in field tests in Zimbabwe. One of the minor components, 2-methoxyphenol, had little antennographic activity but induced upwind flight in the wind-tunnel and appeared to be repellent in field tests.

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