A tick assembly pheromone present in the excretory waste product of the soft tick, Ornithodoros porcinus porcinus (Walton), has been separated by high performance liquid chromatography (HPLC). It has been identified as guanine on the basis of absorption and mass spectral data, and bioassays using nymphs of Argas persicus (Oken). Guanine was active at a low concentration of 8 × 10 −12 M/cm2 of filter paper. Guanine was shown to induce assembly in Amblyomma cohaerens Donitz larvae and Rhipicephalus appendiculatus Neumann adults.
Various purines and ammonium salts tested in the assembly bioassay, and with exception of adenine, were shown to be active for A. persicus.