Attraction of immature stages of the American dog tick (Dermacentor variabilis) to 2,6-dichlorophenol.

To determine whether 2,6-dichlorophenol is solely a sex pheromone, the response to it by the various stages of the American dog tick, Dermacentor variabilis, were compared. In contrast to adults, 2,6-dichlorophenol was attractive to unfed nymphs and to unfed larvae. Use of this chemical also prompted the expression of a novel type of 'feeding' posture behavior in adults. The overlap in attraction to other substituted phenols plus the lack of functional value of this response for larvae and nymphs rules out the possibility that 2,6-dichlorophenol is a general attractant. However, 2,6-dichlorophenol likely plays a dual role as an attachment stimulant in the adult tick.