Responses of the brown dog tick, Rhipicephalus sanguineus, to semiochemicals in a Y-tube olfactometer

Abstract:

The brown dog tick, Rhipicephalus sanguineus, is a pest that can be found worldwide.  This tick poses unique difficulties in management because it can complete its entire life cycle indoors, resulting in infestations in residential areas and kennels.  Acaricide treatments can be costly and have resulted in the development of acaricide resistance in tick populations.  Therefore there is a demand for alternative control methods, and the development of an attract-and-kill system using semiochemicals shows promise.  This study evaluated R. sanguineus response to a variety of semiochemical compounds previously shown to attract other hematophagous arthropods.  Five adults were placed into a Y-tube olfactometer with directionally induced airflow (50 mL/min^-1).  One arm of the Y-tube contained the test chemical and the other arm served as a control.  Both males and females were activated by, and demonstrated significant directional responses to, nine of the 17 semiochemicals tested.  These chemicals included 1% solutions of 1-octen-3-ol, benzaldehyde, benzyl alcohol, hexanoic acid, nonanoic acid, methyl salicylate, o-nitrophenol, 2,6-dichlorophenol and salicylaldehyde, both with and without the addition of carbon dioxide as a synergist. These same chemicals did not induce significant responses at a concentration of 0.01%, whereas tick responses to 0.1% concentrations were varied.  All other chemicals and CO₂ alone did not induce activation or directional response.  Responses did not differ significantly between tick genders or position of testing in the olfactometer.  Tick attractants identified in this study will be evaluated as mixtures, and then in a trap for potential use in brown dog tick management.