Range expansion of Amblyomma americanum and Ixodes scapularis ([Ixodida]: [Ixodidae]) in South Dakota, and new record for Amblyomma maculatum.

This project documents the expanded zoogeographic ranges of the blacklegged tick (Ixodes scapularis Say) and lone star tick (Amblyomma americanum Linnaeus) within eastern South Dakota. The research involves 2 steps. First, tick surveillance was conducted in the eastern counties of South Dakota, spanning March 2021 through August 2022. Surveillance took place along the edge habitat at any accessible natural areas that could be identified as suitable tick habitat. All life stages and species of ticks were collected using a white cloth tick drag, preserved in ethanol, and frozen. Second, the collection of data was contextualized by comparison with prior data in the region to determine if, and to what extent, range expansion had occurred. Distribution maps were created for each year to represent areas where I. scapularis and A. americanum were reported, and changes in species establishment were displayed. This study focused primarily on the Southeastern region of the state, near where I. scapularis populations exist in bordering Minnesota, and A. americanum in Nebraska and Iowa. As of the 2022 sampling season, the only counties where I. scapularis and A. americanum appear to have overlapping ranges are Clay County and Union County. This study also yielded a state record for another human disease vector, the Gulf Coast tick (Amblyomma maculatum Koch) in 2021 and 2022. Target species of tick were detected in nine counties in eastern South Dakota.