4 research outputs found
Directional takeoff, aerial righting, and adhesion landing of semiaquatic springtails
Springtails (Collembola) have been traditionally portrayed as explosive
jumpers with incipient directional takeoff and uncontrolled landing. However,
for these collembolans who live near the water, such skills are crucial for
evading a host of voracious aquatic and terrestrial predators. We discover that
semiaquatic springtails Isotomurus retardatus can perform directional jumps,
rapid aerial righting, and near-perfect landing on the water surface. They
achieve these locomotive controls by adjusting their body attitude and impulse
during takeoff, deforming their body in mid-air, and exploiting the
hydrophilicity of their ventral tube, known as collophore. Experiments and
mathematical modeling indicate that directional-impulse control during takeoff
is driven by the collophores adhesion force, the body angle, and the stroke
duration produced by their jumping organ, the furcula. In mid-air, springtails
curve their bodies to form a U-shape pose, which leverages aerodynamic forces
to right themselves in less than 20 ms, the fastest ever measured in animals. A
stable equilibrium is facilitated by the water adhered to the collophore.
Aerial righting was confirmed by placing springtails in a vertical wind tunnel
and through physical models. Due to these aerial responses, springtails land on
their ventral side 85% of the time while anchoring via the collophore on the
water surface to avoid bouncing. We validated the springtail biophysical
principles in a bioinspired jumping robot that reduces in-flight rotation and
lands upright 75% of the time. Thus, contrary to common belief, these wingless
hexapods can jump, skydive and land with outstanding control that can be
fundamental for survival.Comment: 12 pages, 8 figure