DISENTANGLING THE EFFECTS OF MATING PROPENSITY AND MATING CHOICE IN DROSOPHILA

Area of Science:

• Evolutionary biology
• Behavioral ecology
• Genetics

Background:

• Sexual isolation is key to speciation and is typically measured using choice tests in Drosophila.
• These tests are confounded by mating propensity and discrimination, making interpretation difficult.

Purpose of the Study:

• To investigate the influence of mating propensity on sexual isolation estimates in Drosophila.
• To determine if measuring mating propensity independently can explain choice test outcomes.
• To refine methodologies for assessing intraspecific sexual isolation.

Main Methods:

• Conducted male and female choice tests to measure sexual isolation and mating propensities between Drosophila melanogaster and Drosophila simulans populations.
• Utilized multiple choice tests to assess isolation dynamics and identify potential artifacts.
• Analyzed mating patterns to understand the temporal influence of propensity on isolation.

Main Results:

• Significant deviations from random mating were observed in 31 out of 48 choice tests, correlating with measured mating propensities.
• Mating propensity, rather than discrimination, was found to be a direct factor in estimating sexual isolation.
• Multiple choice tests demonstrated that differing mating propensities can create spurious sexual isolation if tests run too long.

Conclusions:

• Mating propensity is a critical, often underestimated, factor in assessing sexual isolation in Drosophila.
• Standard male and female choice tests may overestimate sexual isolation without accounting for individual mating propensities.
• Recommends terminating multiple choice tests after 50% of matings are observed to mitigate artifacts.