Glass arena used in the bioassays.

<p>A 6 cm diameter glass Petri dish was placed upside down in a larger Petri dish containing a wet piece of filter paper (light grey). Two concentric circles were drawn on the inner surface of the Petri dish, having 1 cm radius (start line or line A) and 2 cm radius (finish line or line B). The treatment was applied with a pipette outside the finish line (dark grey) on the outer surface of the Petri dish in 100 µl volume of solvent. After the complete evaporation of the solvent, a single nymph was placed with a fine paint brush in the center of the arena and the time spent to go from line A over line B was recorded. The dashed line represents the track captured from the video of a single tick moving on an arena treated with a repellent substance (in this case 100 µg of eugenol).