Spatiotemporal dynamics of questing activity by four tick species in the central Great Plains.

Abstract

The distributional expansions of several medically relevant tick species across the central Great Plains create a complex and shifting landscape of tick-borne disease risk. Traditional modeling approaches provide a general picture of distributional potential, but predictions are often static representations of species' ranges. As pathogen transmission is directly linked to tick questing activity, characterizing the spatiotemporal heterogeneity of this behavior is essential to a better understanding of transmission risk and planning of interventions in the area. In this study, we explore novel ecological niche modeling frameworks based on full use of presence-absence data to illuminate the spatiotemporal dynamics of questing activity of four tick species in the central Great Plains region. We processed data from two years of field tick surveillance to derive presence and absence records of active ticks, maximizing sample sizes and making model evaluation more robust. We coupled sampling events with time-specific environmental covariates to leverage longitudinal sampling data still more. We also constrained model response curves to align with fundamental niche theory within a strong conceptual framework. Model outcomes demonstrate both seasonal dynamics of individual species and differences between species in terms of the geographic potential of questing behavior by Great Plains tick species. These modeling approaches provide a more robust basis for understanding ecological drivers of tick questing activity and characterizing the shifting landscape of vector-borne disease risk.