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[Dave Smith <daves AT statenet.com>]

http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2003/02/19/waa19.xml&sSheet=/portal/2003/02/19/ixportal.html

Lesbian Japanese monkeys challenge Darwin's assumptions

By David Derbyshire, Science Correspondent, in Denver

(Filed: 19/02/2003)

The promiscuous sex life of lesbian Japanese monkeys is challenging
one of the central tenets of Charles Darwin. He argued that females
are coy, mate rarely and choose mates to ensure the best genetic
inheritance for their offspring, while males are promiscuous and fight
among themselves for female partners. 

But after studying Japanese macaques in the wild, Dr Paul Vasey, of
the University of Lethbridge, Canada, begs to differ. He found that
bisexuality is common in females and that they often compete with
males for sexual partners. 

"In some populations, female Japanese macaques sometimes prefer
same-sex partners," he told the American Association for the
Advancement of Science in Denver. "That occurs even when they are
presented with sexually motivated, opposite-sex alternatives." 

Males are often prompted into sexual intercourse only if they are
first mounted by females. Dr Vasey said: "Female-male mounting in
Japanese macaques is an adaptation that sexually motivated females
employ to prompt sluggish or uninterested males to copulate with
them." 

He observed that the females gain pleasure from mounting males, often
rubbing themselves against a male's back or stimulating themselves
with their tails. 

Dr Vasey said that once they evolved the capacity to mount males, they
could gain the same sexual gratification from mounting females. "I see
females competing for males all the time," he said. "I see males
ignoring females that are desperate to copulate with them." 

Dr Joan Roughgarden, a biologist at Stanford University, said the
macaque was just one of many species that did not fit Darwin's theory
of sex selection. 

Female langur monkeys promiscuously mated with many males, for
instance. Homosexuality in animals - at least 300 invertebrates
practise it - was also unexplained by Darwin. 

Dr Roughgarden said that a more comprehensive theory of sex selection
should take into account social as well as sexual selection. Mating
could function to build and manage relationships as well as to
reproduce. "Female choice, I am pretty sure, has much more to do with
managing male power than it does with trying to obtain good genes."