Abstract
The associations between sexual selection and kin selection are not well understood in non-social insects, especially in regards to female harm. It has been argued that kin selection is impossible in Drosophila melanogaster based on their inability to recognize kin. However, there is a competing argument that a common rearing environment could promote the development of familiarity, which may function in a similar fashion as relatedness in the kin and sexual selection processes. The research described here was aimed at examining the relationship between familiarity and relatedness in D. melanogaster. To test if D. melanogaster are capable of kin selection via familiarity, two populations of D. melanogaster were used for a full factorial experiment examining mediation of sexual selection through two variables: relatedness and familiarity. If present, kin selection would favor brothers who increase their inclusive fitness by reducing the frequency and/or severity of activities that mediate female harm. Females are harmed each time they are mated. Therefore, if kin selection can mediate female harm (a consequence of sexual selection), and kin selection can occur in response to relatedness and familiarity we should observe lower mating rates and higher offspring outputs in the related, familiar treatment group. After ten replicates of this experiment, I did not observe a significant difference between the four treatment groups. There was no evidence of relatedness nor familiarity mediating female harm. These results may indicate the absence of kin selection in D. melanogaster, or there may be an insufficient signal-to-noise ratio. If the latter, a larger sample size, potentially with larger male to female ratio within treatment groups may be needed to detect a positive result.