Males have an invisible chemical 'essence' that helps prime females for reproduction, according to a new study.
But this invisible trigger has an unfortunate side-effect – the chemicals also speed up the females' ageing process, the researchers have said.
The males do not even need to be present when this happens, the smell left over by tiny amounts of two male pheromones is enough.
The research team, led by a scientist from Northwestern University in Illinois, discovered male animals, through their invisible chemical 'essence,' prime female animals for reproduction.
But the invisible essence also speeds up the females' ageing process.
The researchers claim this effect, although only seen in roundworms and mice, could happen to humans and other creatures.
'The male signals trigger the female to "go for it"—to put more effort into reproduction—but then the body suffers,' said Professor Ilya Ruvinsky, from Northwestern's Weinberg College of Arts and Sciences.
'There is a fine balance between reproduction and body maintenance, and this balance can be tipped by the male. We now are starting to tease apart this complexity.'
The researchers found two signals produced by males that affect female reproduction.
They did this by looking at a transparent roundworm called C. elegan, but they claim their findings could be seen across the animal kingdom.
'We were investigating how animals reproduce under conditions that are closer to natural environments than the cushy life in the laboratory when we found this,' Professor Ruvinsky said.
'One signal causes an earlier onset of puberty in juvenile females. The other slows down aging of the reproductive system in mature females, keeping them fertile longer. However, it also speeds up aging of the body.'
The smell left over by tiny amounts of two male pheromones is enough to trigger these changes, even without the male present.
Pheromones are small molecules produced and released by animals into the environment to alter the physiology or behaviour of other members of the species.
Although the signals target reproduction, even sterile females felt the effects.
'Our results regarding puberty onset echo previous findings in mice,' Professor Ruvinsky said.
'In mammals, males also produce signals that manipulate the timing of sexual maturation of females. This raises an intriguing possibility that a basic mechanism controlling the rate of sexual development is similar in all animals. Because of this universality, our findings may have implications for humans.'
The researchers said their work, described in a paper in the journal Current Biology, could lead to drugs to delay puberty, prolong fertility in humans and even combat ageing.
Male signals do not so much aim to harm females, but instead act to maximize females' readiness for reproduction.
'The harmful effects appear to be collateral damage, rather than the goal,' Professor Ruvinsky said.
