Parasitoid wasp venom re-programs host behavior through downmodulation of brain central complex activity and motor...

Area of Science:

• Neuroethology
• Insect Behavior
• Parasitology

Background:

• The Ampulex compressa wasp manipulates cockroach behavior for reproduction.
• The wasp's venom targets the cockroach's central complex (CX), a key motor control center.

Purpose of the Study:

• To investigate the real-time neural effects of Ampulex compressa venom on the American cockroach's central complex.
• To elucidate the neural mechanisms underlying venom-induced behavioral changes in cockroaches.

Main Methods:

• Chronic in vivo recordings of cockroach central complex (CX) neuronal activity.
• Real-time monitoring of CX activity during and after wasp venom injection.
• Analysis of neuronal firing patterns across distinct temporal phases post-envenomation.

Main Results:

• Wasp venom caused a triphasic change in CX activity: initial reduction, followed by a rebound, and then prolonged suppression.
• Long-term reduction in CX activity correlated with decreased descending interneuron (DIN) activity.
• Suppressed CX and DIN activity led to reduced motor output and locomotion.

Conclusions:

• The study provides a detailed neural pathway explaining how wasp venom induces prolonged hypokinesis in cockroaches.
• The central complex (CX) is a critical target for venom-induced behavioral manipulation.
• These findings offer insights into neurotoxin mechanisms and motor control circuitry.