Directional control by male gypsy moths of upwind flight along a pheromoneplume in three wind speeds

By attaching a reflective strip to the thorax, we documented with video rec ordings in a wind tunnel the spatial orientation of male gypsy moths, Lyman tria dispar, as they flew along a plume of sex pheromone. In and 183 cm s(- 1), moths flew very wind speeds of 61, 122, similar tracks along a pheromon e plume. Moths aimed their thrust closer to upwind in increasing wind speed s using a Poll maneuver. As a result, the orientation of their visual flow field, represented by the slip angle (the angular distance between the dire ction of flight and the longitudinal body axis), remained relatively consta nt. We propose that directional control during self-steered zigzagging is a chieved by rolling, thereby maintaining a set slip angle. Following a roll at the apex of a turn that aligns the moth with its preferred slip angle, a moth banks toward a cross wind leg. By banking moths may maintain a stable image flow at oblique angles to their longitudinal body axis.