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
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.
(Reporting by Kate Kelland; editing by Gareth Jones)
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