The development of the Jamming Avoidance Response (JAR) in Eigenmannia: an innate behavior indeed

Area of Science:

• Neuroscience
• Ethology
• Developmental Biology

Background:

• Gymnotiform electric fish, such as Eigenmannia, possess a Jamming Avoidance Response (JAR).
• The JAR involves shifting electric organ discharge (EOD) frequency to avoid interfering signals from conspecifics.
• The developmental trajectory and innate basis of this behavior are not fully understood.

Purpose of the Study:

• To investigate the developmental emergence of the Jamming Avoidance Response (JAR) in Eigenmannia.
• To determine if the JAR and its developmental schedule are innate or learned.
• To assess the influence of social interaction and sensory experience on JAR development.

Main Methods:

• Continuous behavioral measurements of 164 juvenile Eigenmannia.
• Raising fish in isolation versus social community settings.
• Observing JAR emergence in relation to body length (1.2-1.6 cm) and developmental age (24-32 days).

Main Results:

• A correct JAR emerged in fish aged 24-32 days (1.2-1.6 cm body length).
• Fish raised in isolation showed the same JAR development and timing as socially raised fish.
• An incorrect JAR, involving opposite frequency shifts, appeared transiently in 6% of fish, suggesting initial neural wiring variations.

Conclusions:

• The Jamming Avoidance Response (JAR) and its developmental timing are innate characteristics of Eigenmannia.
• Early variations in the JAR suggest transient immaturities in central nervous system connections.
• JAR development is robust and resistant to experimental manipulation of sensory input, highlighting its fixed developmental program.