Octopamine and tyramine respectively regulate attractive and repulsive behavior in locust phase changes

Area of Science:

• Neuroethology
• Animal Behavior
• Chemical Ecology

Background:

• Aggregative and solitary behaviors are common in animals.
• Locusts exhibit reversible phase transitions between gregarious and solitary states.
• The neurotransmitter mechanisms driving locust attraction and repulsion are not well understood.

Purpose of the Study:

• To investigate the neurotransmitter basis of attraction and repulsion in locusts.
• To identify the specific signaling pathways involved in locust behavioral plasticity.
• To elucidate the roles of octopamine and tyramine in mediating social behavior.

Main Methods:

• Behavioral assays measuring attraction/repulsion to gregarious volatiles.
• RNA interference to assess the function of octopamine receptor α (OARα) and tyramine receptor (TAR) signaling.
• Monoamine injections to observe effects on olfactory preference.
• Correlation analysis of neurotransmitter activity with behavioral responses.

Main Results:

• Locusts' attraction/repulsion to volatiles changes with social context.
• Octopamine-OARα signaling mediates attraction in gregarious locusts; tyramine-TAR signaling mediates repulsion in solitary locusts.
• Manipulating OARα and TAR signaling reversed locust behavioral responses, demonstrating their causal roles.

Conclusions:

• Invertebrate-specific octopamine-OARα and tyramine-TAR signaling pathways are key regulators of behavioral plasticity in locusts.
• These neurotransmitter systems mediate attraction and repulsion, driving the phase transitions between solitary and gregarious behaviors.
• Understanding these mechanisms provides insight into the neurobiology of social behavior.