Blacklegged Ticks, Ixodes scapularis , Respond to Sex‐Attractant Semiochemicals of Male Deer Mice, Peromyscus maniculatus

ABSTRACT Ticks are obligate ectoparasites that blood‐feed on a variety of vertebrate hosts including rodents such as deer mice, Peromyscus maniculatus bairdii . Tick attraction to rodent semiochemicals has been reported but the semiochemicals mediating the attraction have rarely been identified. As recently reported, male deer mice disseminate sex‐attractant semiochemicals (9 ketones and testosterone) from their urine and feces, which are highly attractive to conspecific females. In two‐choice still‐air olfactometers, we tested the hypothesis that ticks eavesdrop on these sex‐attractant semiochemicals to locate deer mouse hosts. Female blacklegged ticks, Ixodes scapularis —but not female lone star ticks, Amblyomma americanum , or American dog ticks, Dermacentor variabilis —were attracted to urine‐ and feces‐soiled bedding of male deer mice. Furthermore, female blacklegged ticks were attracted to the complete sex‐attractant semiochemical blend of male deer mice, but not to the ketones alone or to the testosterone alone. The attractiveness of these deer mouse semiochemicals to female blacklegged ticks could not be enhanced by adding carbon dioxide and ammonia gases (generic vertebrate urine cues) to the sex‐attractant semiochemical blend of male deer mice. Our data suggest that female blacklegged ticks exploit deer mouse sex‐attractant semiochemicals to inform questing decisions. Synthetic deer mouse semiochemicals could be combined with a contact acaricide as a tick monitoring or control tactic.