Surveying African Drosophila melanogaster Populations for Female Mate Preference

Female mate choice is a strong factor shaping the evolution of mating behaviors and ultimately speciation through reproductive isolation. Female mate choice can rapidly diverge between populations. We use mating behavior in Drosophila melanogaster as a model for studying the evolution of mating interactions. D. melanogaster occurs globally with differences in behaviors between populations.  African females are known to reject non-African males, suggesting a role for sexual selection in population differentiation. We tested how common this female behavior is by examining multiple African female genotypes using no-choice mating assays, with known “choosy” and “non-choosy” strains as controls. We found that mating behavior varied across genotypes, but we did not see extreme choosiness compared to previously studied African strains. These results indicate that strong female preference is not uniform across African populations and may reflect ongoing evolutionary dynamics such as migration back into Africa. This could suggest that choosiness has a cost if it is decreasing in frequency over time.

We used no-choice mating assays to assess whether strong female preference is common in African populations of D. melanogaster. As controls, we included a previously characterized “choosy” African strain (Z30-42) and a non-choosy strain (DRGP882). The remaining African strains were collected from Zambia and were generously provided by John Pool.

• Our pattern may reflect the migration of non-choosy alleles back into African populations.

• These strains were chosen because they lack inversions. Female choosy behavior could be associated with specific African inversions.

Future Directions

• We are currently testing 7 additional African genotypes.

• Choice assays can be used to detect more subtle female preferences

• Investigate other African-specific traits including pheromones and courtship behavior