Figure 6.

A sketch illustrating the measurement of a head distance d_head and alignment angle θ. d_head is calculated as the distance between the parasite head and the closest membrane vertex (brown color). θ is determined as the angle between the directional vector n of the parasite and the normal of a triangular face (green arrow) whose center is closest to the parasite head. The alignment angle is calculated only if the head of the parasite is within a certain interaction range with the membrane, as indicated by the blue circle. To see this figure in color, go online.