Investigations into the volatility of female pheromones and the aggregation-inducing property of guanine in Argas (Persicargas) walkerae.

During investigations into the volatility of female pheromones of A. walkerae in a Y-shaped olfactometer, engorged conspecific male ticks responded weakly both to female-contacted filter paper discs and to intact females enclosed in nylon bags. In tests in which female-contacted filter paper discs were separated from engorged male ticks by means of a screen, no aggregation was observed. However, replete male ticks showed a vigorous response to liquefied air and hexane-trapped volatiles collected from intact females. Guanine showed a potent aggregation attraction for engorged and unfed larvae and 1st and 2nd stage nymphal ticks as well as for male and female imagines of A. walkerae over a wide concentration range. It is concluded that at least 2 pheromones, 1 volatile and 1 non-volatile, are operative in the communication system of this tick species.