Disruptive selection for sternopleural bristle phenotypes in Drosophila ananassae

Area of Science:

• Evolutionary Biology
• Genetics
• Behavioral Ecology

Background:

• Disruptive selection is crucial for maintaining genetic variation and initiating speciation.
• It favors extreme phenotypes over intermediate ones, influencing population genetic structure.
• Understanding disruptive selection's role in behavioral isolation is key to speciation research.

Purpose of the Study:

• To investigate the effect of disruptive selection on sternopleural bristle number on behavioral isolation in Drosophila ananassae.
• To determine if artificial selection for extreme bristle phenotypes can lead to reproductive isolation.

Main Methods:

• Applied disruptive selection for high and low sternopleural bristle numbers for 12 generations in Drosophila ananassae.
• Assessed mating patterns using an Elens-Wattiaux mating chamber with a multiple-choice technique.
• Analyzed mating data using chi-squared tests and calculated isolation estimates.

Main Results:

• Disruptive selection effectively altered sternopleural bristle phenotypes, as indicated by realized heritability and statistical significance.
• No evidence of significant sexual or behavioral isolation was observed between selected lines after 5 and 12 generations.
• Mating propensity differences were observed, influenced by sternopleural bristle phenotypes.

Conclusions:

• Disruptive selection for sternopleural bristles in Drosophila ananassae does not induce behavioral isolation.
• Selection effectively modified the target phenotype but failed to initiate reproductive isolation.
• The study highlights that changes in mating propensity, influenced by phenotypic traits, can occur without full behavioral isolation.