Wind gates olfaction-driven search states in free flight

Area of Science:

• Animal behavior
• Neuroethology
• Sensory biology

Background:

• Organisms use fluid motion cues for source localization.
• Olfactory search strategies in wind are known, but less so in still air or with unreliable cues.

Purpose of the Study:

• Investigate how Drosophila melanogaster adjusts olfactory search strategies in response to wind presence and direction.
• Determine the sensory mechanisms underlying wind estimation and search behavior.

Main Methods:

• Developed an optogenetic system for precise "virtual" olfactory stimuli delivery.
• Observed free-flying Drosophila melanogaster behavior in laminar wind and still air.

Main Results:

• Flies turn upwind in laminar flow using rapid (∼100 ms) turns, indicating prior wind estimation.
• In still air, flies exhibit a stereotyped "sink and circle" search with consistent turn bias.
• Deceleration and rapid turns occur upon odor onset in both conditions, suggesting active sensing.

Conclusions:

• Drosophila melanogaster assesses ambient wind conditions before initiating distinct search strategies.
• Active sensing maneuvers like deceleration and turns help flies gauge wind properties for effective olfactory navigation.