Flies who play the mating game while also living with their brothers are gentler to females during sex and tend to hassle them less, according a study by British scientists.
The study found that unrelated male flies compete more fiercely for female attention than related flies, pestering them more often for sex and leaving them little time to sleep or eat.
“Brothers don’t need to compete so much with each other for female attention since their genes will get passed on if their sibling mates successfully anyway,” said Dr Tommaso Pizzari of Oxford University’s zoology department, who led the study.
“Their more relaxed attitude to mating results in fewer fights and they also harm the females less as their courting is not so aggressive.”
The scientists also found that female mates of competing unrelated flies tend to have shorter reproductive lives and produce fewer offspring when males constantly harass them.
According to the research, published in the journal Nature on Wednesday, fly courtship is complex and involves a kind of foreplay of singing and genital licking.
“Repeated harassment of this sort may physically damage females as well as leaving them less time to get the food and rest they require for a healthy life,” Pizzari said.