Hawkmoths regulate flight torques with their abdomen for yaw control

Area of Science:

• Insect flight dynamics
• Biomechanics
• Animal locomotion

Background:

• Animals use body parts like tails for high-speed stabilization.
• In flying insects, abdominal inertia can influence flight posture and control.
• The hawkmoth (Manduca sexta) abdomen is substantial, potentially aiding in inertial force redirection.

Purpose of the Study:

• To investigate the interaction between wing and abdominal torques for flight control in hawkmoths.
• To quantify the individual contributions of wings and abdomen to yaw torque production.
• To understand how abdominal movements contribute to flight maneuverability.

Main Methods:

• Studied the yaw optomotor response of Manduca sexta using a thoracic torque sensor.
• Utilized moths with ablated wings and fixed abdomens to isolate torque contributions.
• Employed frequency-domain analysis and a two-link system model for data interpretation.

Main Results:

• The hawkmoth abdomen moved antiphase to visual yaw stimuli, affecting head and total torque.
• Abdomen torque was smaller than wing torque but significant at higher stimulus frequencies (∼80% of wing torque).
• Abdomen flexion was shown to constructively redirect thoracic torques, enhancing steering.

Conclusions:

• The hawkmoth abdomen plays a crucial role in regulating wing torques during flight.
• Abdominal movements can modulate flight trajectories and increase maneuverability.
• The study highlights the importance of considering abdominal contributions in tethered insect flight experiments.