Evaluating the changes in questing behavior of lone star ticks (Amblyomma americanum) following a sublethal exposure to a pyrethroid-neonicotinoid product

In the southeastern US, Amblyomma americanum (the lone star tick), bites humans more frequently than any other tick species. Lone star ticks can transmit Ehrlichia spp., and they are also implicated in the acquisition of an allergy to red meats. In spite of this, most tick research is focused on Ixodes scapularis and Dermacentor variabilis, the predominant vectors of Lyme disease and Rocky Mountain spotted fever, respectively. Due to the lack of focus on A. americanum, there are no established best practices for this species and liquid pesticides are the mainstay for control. In spite of their widespread application, we have a fairly limited understanding of pesticidal efficacy against lone star ticks. This is a problem, because although insecticides have an expected direct impact on mortality, they also have unexpected indirect effects on arthropod behavior that might impact vector-borne disease transmission and program success. Thus, in this study, we assessed the sublethal effects of a widely used combination product containing both a neonicotinoid and a pyrethroid for i) overall efficacy and ii) unexpected behavioral changes in lone star ticks after sublethal exposure. Behavioral changes after sublethal exposure to pesticides may have important consequences for human-tick interactions that would impact tick control and, potentially, human disease incidences.