Sibling relationships can alter sexual behaviour in fruit flies

Fruit flies (Drosophila melanogaster) adopt a mating strategy based on sibling relationships and the sexual familiarity of potential mates.

Male fruit flies like to have a variety of unknown sexual partners, but female fruit flies prefer the same mate or their “brothers-in-law”.

Although this “in-law effect” has no clear explanation, it is speculated that males benefit from mating with dissimilar females through the higher genetic diversity of their offspring.

Females, on the other hand, may prefer to mate with familiar males to avoid the health risks posed by allowing sperm from multiple partners into their bodies.

Read more at Oxford University