They said males increase their fitness by acquiring more mates; however, this is often not the case for females.

Previous studies of sexual conflict generally have limited individual movement, emphasizing local competition.

The new study showed that groups in which a more gentlemanly approach to mating prevails do better on the whole, even though jerks generally outperform the nice guys when they have to compete one-on-one.

For the study lead author Omar Tonsi Eldakar termed the insects as 'nice guys' vs 'jerks;' his adviser, David Sloan Wilson, a co-author of the paper and a distinguished professor of biological sciences at Binghamton, termed them 'gentlemen' vs 'psychopaths.'

"The presence of psychopaths dramatically reduced the productivity of the population," said Wilson.

"When all the males were gentlemen, the females laid about three times more eggs than they did when all the males were psychopaths. And yet within each group the psychopaths were doing better than the gentlemen. How do the gentlemen persist if they're disadvantaged within the group?"

Once the females could move between groups, the researchers had their answer. The researchers devised a wading pool equipped with special doors that could restrict movement between groups or allow the insects to move freely.

"When they opened the doors, the females would leave whenever a psychopath came around," Wilson said.

"The whole thing resulted in a heterogeneity in which the females were clustered with the gentlemen. It''s the movement of individuals that creates these differences between groups that favour nonaggressive males," Wilson added.