  Flight is a complicated task at small scales in part due to the ubiquitous
unsteady air which contains it. Flying organisms deal with these difficulties
using active and passive control mechanisms to steer their body motion. Body
attitudes of flapping organisms are linked with their resultant flight
trajectories and performance, yet little is understood about how discrete
unsteady aerodynamic phenomena affect the interlaced dynamics of such systems.
In this study, we examined freely flying bumblebees subject to a single
discrete gust to emulate aerodynamic disturbances encountered in nature.
Bumblebees are expert commanders of the aerial domain as they persistently
forage within complex terrain elements. Physical obstacles such as flowers
produce local effects representative of a typified gust which threatens the
precise control of intricate maneuvers. By tracking the 3D dynamics of bees
flying through gusts, we determined the sequences of motion that permit flight
in three disturbance conditions. Bees repetitively executed a series of passive
impulsive maneuvers followed by active recovery maneuvers. Impulsive motion was
unique in each gust direction, maintaining control purely by passive
manipulation of the body. Bees pitched up and slowed-down at the beginning of
recovery in every disturbance, followed by corrective maneuvers which brought
attitudes back to their original state. Bees were displaced the most by the
sideward gust, displaying large lateral translations and roll deviations.
Upward gusts were easier for bees to fly through, causing only minor flight
changes and minimal recovery times. Downward gusts severely impaired the
control response of bees, inflicting strong adverse forces which sharply upset
trajectories. Bees used interesting control strategies when flying in each
disturbance, offering new insights into insect-scale flapping flight and
bio-inspired robotic systems.
