Playboys `have shorter lives`, reveals a new study

Updated: Sep 06, 2010, 12:14 PM IST

Washington: Playboys, beware! You may die early, say researchers.

A new study, led by the University of New South Wales, claims that males who are focused on pursuing multiple partners usually have stunted growth and die young as they can neglect essential needs like eating.

The findings suggest that male promiscuity is not more common, despite its potential evolutionary advantages, as it`s subject to natural limitations, the `Journal of Evolutionary` Biology` reported.

Lead researcher Alex Jordan said: "Perhaps it`s nature`s way of telling males to be more faithful to their sexual partners. We wondered why the natural world is not a more promiscuous place.

"For males, especially, mating with a high number of partners results in the greatest reproductive success, so you would think that the rule should be the more the better.

"In fact, our research revealed that males pay a significant cost of promiscuity that places an upper limit on the number of sexual partners they can have throughout their lifetime."

For the study, the researchers conducted behavioural trials with tropical fish, as well as examining the lifetime costs of male reproduction, the first such study involving vertebrate animals.

Males of many species increase their reproductive effort with unfamiliar mates -- a phenomenon known as the Coolidge effect.

When the male fish were regularly supplied with new unfamiliar females throughout their life, they spent less time looking for food and more time pursuing the females. Males living with unfamiliar females also grew more slowly and to a smaller adult size, and tended to die sooner.

In contrast, males living with a single partner ate regularly, grew steadily and lived longer.

"The considerable costs of promiscuity to individuals involved reveal a natural limitation on promiscuous behaviour, previously undescribed in vertebrates. Perhaps those who wish for a more promiscuous existence will see this as a warning.

"What it tells us scientifically is that the evolution of extreme promiscuity seems to be curtailed by physiological costs involved -- although promiscuity has advantages, the trade-off might be too great in the long-term," Jordan said.

PTI