title: Whiteflies stabilize their take-off with closed wings.
abstract: The transition from ground to air in flying animals is often assisted by the legs pushing against the ground as the wings start to flap. Here, we show that when tiny whiteflies (Bemisia tabaci, body length ca. 1 mm) perform take-off jumps with closed wings, the abrupt push against the ground sends the insect into the air rotating forward in the sagittal (pitch) plane. However, in the air, B. tabaci can recover from this rotation remarkably fast (less than 11 ms), even before spreading its wings and flapping. The timing of body rotation in air, a simplified biomechanical model and take-off in insects with removed wings all suggest that the wings, resting backwards alongside the body, stabilize motion through air to prevent somersaulting. The increased aerodynamic force at the posterior tip of the body results in a pitching moment that stops body rotation. Wing deployment increases the pitching moment further, returning the body to a suitable angle for flight. This inherent stabilizing mechanism is made possible by the wing shape and size, in which half of the wing area is located behind the posterior tip of the abdomen.
authors.affiliation: Department of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel gribak@post.tau.ac.il.
authors.forename: Gal
authors.initials: G
authors.lastname: Ribak
authors.affiliation: Department of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel.
authors.forename: Eyal
authors.initials: E
authors.lastname: Dafni
authors.affiliation: Department of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel.
authors.forename: Dan
authors.initials: D
authors.lastname: Gerling
mesh_terms: D000054:Acceleration; D000818:Animals; D001696:Biomechanical Phenomena; D005426:Flight, Animal / Q000502:physiology*; D006430:Hemiptera / Q000502:physiology*; D008954:Models, Biological; D009043:Motor Activity / Q000502:physiology; D013997:Time Factors; D019415:Torque; D014921:Wings, Animal / Q000502:physiology*
keywords: Flight stability; Jumping; Pitch; Tumbling; Wing deployment