Thoracic Temperature Stabilization byn Blood Circulation in a Free-Flying Moth

Area of Science:

• Insect physiology
• Thermoregulation
• Aerodynamics

Background:

• The sphinx moth (Manduca sexta) is known for its ability to maintain a stable thoracic temperature during flight.
• Understanding insect thermoregulation is crucial for comprehending flight performance and ecological adaptation.

Purpose of the Study:

• To investigate the physiological mechanisms underlying thoracic temperature control in the sphinx moth during flight.
• To determine the role of the dorsal vessel and thoracic scales in Manduca sexta thermoregulation.

Main Methods:

• Experimental manipulation of the dorsal vessel (tying off) in Manduca sexta.
• Observation of flight behavior and thoracic temperature at varying ambient temperatures.
• Removal of thoracic scales to assess their contribution to temperature regulation.

Main Results:

• Tying off the dorsal vessel disrupted temperature control, leading to overheating and flight cessation at 23°C.
• Removal of thoracic scales allowed flight at 23°C despite dorsal vessel occlusion.
• The study identified heat transfer from the thorax to blood in the dorsal vessel and subsequent abdominal heat dissipation as a key mechanism.

Conclusions:

• The dorsal vessel and associated blood flow are critical for maintaining thoracic temperature in flying Manduca sexta.
• Thoracic scales play a role in heat dissipation, aiding thermoregulation.
• This research elucidates a circulatory mechanism for active thermoregulation in insects.