Unexpected rewards induce dopamine-dependent positive emotion-like state changes in bumblebees

Area of Science:

• Neuroethology
• Animal behavior
• Invertebrate neuroscience

Background:

• Understanding emotion-like states in invertebrates is limited.
• The neural mechanisms underlying positive affect in non-mammals are poorly understood.

Purpose of the Study:

• To investigate the presence of dopamine-dependent positive emotion-like states in bumblebees.
• To explore how these states influence decision-making and behavioral responses.

Main Methods:

• Behavioral experiments involving rewarding and unrewarding cues.
• Assessment of responses to ambiguous cues after sucrose consumption.
• Pharmacological manipulation using a dopamine antagonist (fluphenazine).
• Analysis of foraging behavior recovery after simulated predator attacks.

Main Results:

• Bumblebees exhibited positive responses to ambiguous cues after sucrose reward, indicating an emotion-like state.
• Sucrose consumption reduced the time to resume foraging post-predator simulation.
• These behavioral changes were blocked by fluphenazine, confirming dopamine's role.
• Results indicate the effect is not due to increased general exploratory behavior.

Conclusions:

• Dopamine mediates positive emotion-like states in bumblebees.
• These findings advance the understanding of fundamental neural elements of emotion.
• The study suggests emotion states significantly impact decision-making in animals, including invertebrates.