Evidence for an Assembly Pheromone(S) Produced by Males of the Bont Tick, Amblyomma Hebraeum (Acarina: Ixodidae)

Abstract

Evidence is presented for the existence of an assembly pheromone in the tick Amblyomina hebraeum Koch. Males were found to aggregate in clusters around both males which had preattached to cattle or rabbits and extracts of such males. The existence of pheromone was also demonstrated using a Y-shaped olfactometer. Females were found to assemble around sexually active males or extracts of such males but failed to attach to various hosts in the absence of fed males or extracts of such males. The time required for adult male ticks to attach to hosts treated with pheromone extract was shorter than the attachment time on untreated control hosts. Extracts of fed males attracted adult ticks for 3 days after the application. Production of male assembly pheromone was associated with feeding. Males which fed less than 4 days failed to attract ticks. A weak response to the attached males was seen on the 5th day; this response increased during the 6th day and reached a peak 8 days after feeding had started. Migration and behavior of adult ticks was influenced by the presence of an assembly pheromone released by fed males. A model which explains this behavior is suggested.