An investigation into the emission sites of the volatile pheromone produced by females of Argas (Persicargas) walkerae.

By leaving open in turn the genital orifice, coxal apertures and anus, the present study has shown that engorged female Argas walkerae release at least 1 volatile pheromone mainly, or maybe exclusively, from the genital aperture. Although this aggregation-inducing pheromone is perceived by all post-larval stages, engorged males of A. walkerae react most strongly. A possible, but only slight, emission through the anus and the coxal aperatures is also indicated. Most probably, this airborne biosubstance is the primary directing and orienting pheromone in the interrelations between members of this tick species.