Davidson College Grad, Madeline Seagle ’20, studied tick abundance in the Davidson Area
Below are excerpts from recent local research on our local tick population
By Madeline Seagle
During the summer of 2019, students of Dr. Kevin Smith’s lab at Davidson College surveyed tick species in Davidson and other locations across North Carolina. Dr. Smith had noticed during his time of field research in Davidson that he rarely saw ticks, which inspired our research project to explore tick abundance and species diversity in the Davidson area. We expanded the project to survey four other locations in North Carolina: South Mountains State Park, Stone Mountain State Park, Duke Forest, and Morrow Mountain. These other locations served as a comparison group to determine if the low tick abundance spans other areas of the state.
To survey for ticks we used cloth drags, CO2 traps, and leaf litter sampling. Cloth drags pick up ticks that are on the forest floor or grass. We used CO2 traps to attract ticks by mimicking mammal presence and are left out overnight. Sometimes, ticks hide in the leaf litter and topsoil, so we collected samples that we brought back to the lab. Ticks tend to move to where soil and leaves are damp, so we placed lights above the leaf litter samples to promote movement downwards into a jar of ethanol.
During the summer, we surveyed 19 sites with cloth drags in Davidson, which covered a total of 3,800 square meters. We set out CO2 traps for 16 nights and collected leaf litter samples at 6 sites. From all of this sampling, we only found nine ticks, which were all adult dog ticks (Dermacentor variabilis). We repeated cloth drags during the fall season at 18 sites and set out CO2 traps and collected leaf litter from the same sites as the summer. During the fall season, we only found one tick, which was a lone star tick (Amblyomma Americanum) larvae and it was found in the leaf litter.
We found a similarly low abundance of ticks at our other study sites, and Stone Mountain was the only location at which we found a black-legged tick (Ixodes Scapularis), which carry Lyme disease. Black-legged ticks are much more abundant in Virginia, causing higher rates of Lyme disease and other tick-borne diseases. Stone Mountain is located near the border of Virginia, so our finding could indicate the beginning of a southward movement of black-legged ticks into North Carolina.
Our surveys in Davidson confirmed observations of low tick abundance and we found comparable low abundance in other areas of the state. Rates of Lyme disease and other tick-borne diseases are significantly lower in North Carolina than states to the north, which is likely due to our low tick abundances, particularly black-legged ticks. These findings indicate that there could be ecological factors, such as forest and host composition, that limit our abundance of ticks.