Social effects on fruit fly courtship song

Area of Science:

• Behavioral Ecology
• Neuroethology
• Evolutionary Biology

Background:

• Courtship behavior in Drosophila is generally considered innate but shows significant plasticity.
• Exposure to acoustic signals can alter courtship traits, potentially impacting reproductive isolation.
• The social plasticity of male courtship song itself remains largely unexplored.

Purpose of the Study:

• To investigate the social plasticity of male courtship song in the Drosophila melanogaster subgroup.
• To determine if specific song traits (interpulse interval and sinesong frequency) are socially modifiable.
• To explore the role of learning in observed song plasticity.

Main Methods:

• Examined courtship song plasticity in two species within the Drosophila melanogaster subgroup.
• Males were exposed to conspecific or heterospecific social partners or reared in isolation.
• Assessed song traits including interpulse interval (IPI), sinesong frequency (SSF), and song burst duration.
• Utilized Drosophila melanogaster mutants affecting short- and medium-term memory.

Main Results:

• Neither interpulse interval (IPI) nor sinesong frequency (SSF) showed plasticity after social exposure.
• Males exposed to social partners (con- or heterospecific) produced longer song bursts than isolated males.
• Mutations affecting short- or medium-term memory did not alter the response to the social environment, suggesting a lack of learning.

Conclusions:

• Male courtship song *amount* (duration) is plastic and influenced by the social environment.
• Song structure (IPI and SSF) appears relatively inflexible, possibly due to selection against hybridization.
• Social plasticity in song output may confer advantages in intrasexual competition.