Neural responses from the wind-sensitive interneuron population in four cockroach species

Area of Science:

• Neuroethology
• Insect sensory systems
• Comparative neurobiology

Background:

• The cercal sensory system in insects is crucial for predator detection and escape behaviors.
• Different cockroach species exhibit varying escape responses to wind stimuli, linked to flight muscle type and wing presence.
• Wind-sensitive interneurons (WSIs) are key components in processing wind information for motor control.

Purpose of the Study:

• To investigate the role of wind-sensitive interneurons (WSIs) in mediating differential wind-evoked escape behaviors in four cockroach species.
• To characterize the stimulus-response curves and firing rates of WSIs across species with varying escape capabilities.
• To analyze the population activity and individual unit responses within the WSI network.

Main Methods:

• Extracellular recordings were used to measure WSI activity in four cockroach species.
• Stimulus-response (S-R) curves and spike firing rates were generated to quantify WSI responses to wind.
• Cluster analysis examined the activity patterns of individual WSI units within the population response.

Main Results:

• All four species possessed ascending WSIs in their abdominal connectives.
• Gromphadorhina portentosa exhibited the weakest WSI responses to wind, correlating with its lack of escape behavior.
• Blaberus craniifer showed stronger WSI responses than Periplaneta americana or Blattella germanica, despite differences in flight ability.
• Individual WSI unit activity patterns were conserved across the studied species.

Conclusions:

• WSI responses to wind stimuli vary among cockroach species, aligning with their distinct escape behaviors.
• The conserved activity of individual WSI units suggests a fundamental neural mechanism for wind processing.
• Differences in WSI population responses likely contribute to the observed variations in escape behaviors and flight capabilities.