Structure-activity studies on analogues of 4-methylguaiacol, a cattle anal odour constituent repellent to the brown ear tick (Rhipicephalus appendiculatus).

Previously, 4-methylguaiacol, a major constituent of cattle anal odour, was found to have a high repellency on Rhipicephalus appendiculatus. In the present study, 10 structural analogues of the phenol were tested for repellency against R. appendiculatus in order to assess the effects of (i) absence or presence of the 4-alkyl group of varying length, (ii) inclusion of a double bond in the 4-alkyl chain, (iii) linking the two phenolic oxygen in a methylenedioxy bridge, (iv) replacement of the OCH with CH and inclusion of another CH at position 6, and (v) presence of an additional OCH group at position 6.

Characterisation of cattle anal odour constituents associated with the repellency of Rhipicephalus appendiculatus.

Adults of the Brown Ear Tick (Rhipicephalus appendiculatus) have a predilection for feeding inside and around the ears of cattle and other hosts. A previous study has shown that the tick locates the host ears by 'push-pull' deployment of a repellent blend emitted at the anal region and an attractant blend emitted at the ears. Interestingly, the two odours play reverse roles with Rhipicephalus evertsi, which prefer to feed around the anal region.