This brief footage illustrates a contact irritancy bioassay for blacklegged ticks (Ixodes scapularis) on permethrin-treated fabric. In the test, tick nymphs are placed on the textile, which is held at a 45-degree angle. The ticks can be seen showing agitated behavior (the “hot-foot” effect) and one falls off (i.e., is repelled). (Video credit: Neeta Connally, Ph.D.)