Behavioural and electrophysiological (EAG) studies were undertaken to determine the olfactory selectivity of the antennae of Glossina morsitans morsitans Westwood and Glossina pallidipes Austen to phenolic kairomones. Responses of both species to 3-alkylphenols increased as the alkyl chain increased from one carbon atom to three, while the opposite trend was observed with 4-alkylphenols. These results indicated that 4-cresol and 3-n-propylphenol are the most stimulatory of the two respective groups of phenols. However, comparison of the responses indicated differences in the sensitivities of the chemoreceptor systems of the two species. Hence different compositions of the phenols may be required to best attract these species. Probable interactions of the phenols with the binding sites on the receptor surface are discussed.

Behavioural-antennal responses of tsetse to buffalo urine, which has been identified as a potent olfactory attractant, were investigated. Tsetse Glossina morsitans morsitans rapidly raised their antennae upon stimulation with the odour of buffalo urine. Flies showed a clear preference for the undiluted urine, though antennal responses even to 100,000 × diluted urine were significantly different from control, indicating the high efficacy of the attracting compounds present in it. Fresh buffalo urine was the most attracting as compared to 4- and 8-day-old urine. The dichloromethane extract of fresh urine was as active as the natural product, indicating that the attracting compounds were extractable into dichloromethane. Under laboratory conditions, responses of males to the urine were significantly more than females.