Mating environments mediate the evolution of behavioral isolation during ecological speciation.

Area of Science:

• Evolutionary Biology
• Speciation Research
• Behavioral Ecology

Background:

• Behavioral isolation is a crucial initial step in the speciation process.
• Previous research indicates ecological selection can drive behavioral isolation, but factors influencing its evolution require deeper understanding.
• The mating environment's role in mediating behavioral isolation is complex, potentially involving direct selection on sexual interactions or constraints on trait evolution.

Purpose of the Study:

• To investigate how different mating environments affect the evolution of behavioral isolation.
• To determine if ecological speciation, driven by mating environment, directly causes behavioral isolation or if the environment constrains its evolution.
• To explore the interplay between mating environment, larval environment adaptation, and the emergence of assortative mating.

Main Methods:

• Experimental evolution with 28 fly populations.
• Populations evolved under distinct mating and larval environments.
• Quantification of behavioral isolation and assortative mating patterns.

Main Results:

• Behavioral isolation did not evolve maximally between populations from different mating environments, challenging direct ecological speciation via mating environment.
• One mating environment significantly promoted the evolution of behavioral isolation, while the other did not.
• Assortative mating evolved only when populations adapted to different larval environments within the conducive mating environment, underscoring the role of ecological divergence.
• The mating environment that facilitated behavioral isolation exhibited less sexual conflict.

Conclusions:

• Mating environments play a critical role in mediating the evolution of behavioral isolation.
• Ecological speciation, driven by adaptation to divergent larval environments, is essential for behavioral isolation to evolve, even in a conducive mating environment.
• Reduced sexual conflict in mating environments may be a key factor promoting the evolution of behavioral isolation.