If males can make it through a stressful adolescence and come out on top then females love it, finds a new study in rats. However, if a male goes through a stressful time in his youth and then struggles socially then it becomes a turn-off to females.
In the study, published in the journal Hormones and Behaviour, male rats were either given a stressful adolescence – by making them switch cages regularly in order to to settle into a new social group again and again – or were allowed to grow up in the same group.
Two male rats – one that had a stressful youth and one that didn't – were placed in a cage with a female. The scientists measured how long she would visit each male and how long she would spend with each, as a measure of which she preferred.
The rat that the female chose to hang out with more as a prospective mate depended on the male's social dominance and his reaction to the stressful adolescence.
If the rat was a confident, socially dominant male, then a stressful past made him pique the female's interest more than the rats with an ordinary youth. The resilience necessary to thrive even in a difficult environment is likely to be the reason for this appeal, study author Nicole Cameron, a psychologist at Binghamton University, State University of New York, told IBTimes UK.
On the flip side, if the rat with a stressful past was a meek, socially submissive male, then the females preferred the rat who had had not been stressed as an adolescent. "There's probably an inherent vulnerability to stress that would be pushing the males who are submissive to be more submissive in a stressful environment," Cameron says.
Of rats and men
Stress is likely to be playing the same role in humans. "Some people are more vulnerable to stress than others, so stress can push a positive or negative outcome depending on their vulnerability," she says.
"If an adolescent grows up in a stressful environment, he is either going to be thriving in this and becoming an even greater achiever in adulthood, or he is going to be affected negatively and become somebody that cannot form relationships."
In addition, a stressful adolescence could lead to problems with male reproductive health as the endocrine system – which produces and regulates hormones in the body – is very vulnerable to stress.
"Stress during adolescence affects the development of the endocrine system, which is implicated in sexual reproduction," says Cameron. "So the effect is at multiple levels. If you are in a stressful environment and you don't thrive, your reproductive system is also impacted by your stress."