Individuals often migrate from their place of origin in a relatively slow pace. As such, related individuals frequently interact. Relatedness between two individuals is defined as the percentage of genes in those two individuals that are identical by common ancestry. My PhD project at University of Oxford focuses on the mechanisms through which relatedness affects sexual interactions of the common fruit fly, Drosophila melanogaster and the red jungle fowl, Gallus gallus.

Our dance depicts the social and sexual behavior of the common fruit fly. Fruit flies are attracted by the smell of rotting fruit where they collect, feed and interact. Males compete against one another for female mates. In addition, males perform a sequence of courtship behaviors. First, they tap and chase the females. Thereafter, they encircle the females while playing a song by vibrating their wings. Then, the males orient themselves at the rear of the females’ abdomen to lick their body. Finally, males attempt copulation. Females can reject the males’ advances with several responses such as flicking of wings and kicking.

This choreography also illustrates how male-male relatedness can reduce the intensity of male-male competition and affect female choice. When two males are related, they are predicted to show less aggression towards each other. Also, females preferentially mate with males that are related to the first mates because there might be immunological and survival costs associated with mating with males that are unrelated to their first mate. Furthermore, we demonstrate the importance of smell in mediating the recognition of relatedness.