London, May 21 (IANS) Sexual conflict between males and females can lead to changes in the shape of their genitals, finds a new research conducted on burying beetles.
The findings showed that beetles genitals change shape when mating rates are high as females try to keep males at bay.
"It's fascinating how genital evolution can happen so fast - in ten generations - showing how rapidly evolutionary changes can occur," said Paul Hopwood from the University of Exeter in Britain.
The conflict over how often mating takes place could lead to males evolving longer penis-like organs and females larger 'claws' on their genitalia, within ten generations.
Also, changes in one sex were reflected by changes in the shape of the other sex, showing there was co-evolution.
Our results show that sexual conflict over mating can lead to co-evolutionary changes in the shape of the genitals of burying beetles," added Hopwood.
Sexual conflict over mating occurs because, whilst having lots of sex is usually good for a male -- as it increases the number of offspring he is likely to produce -- it is not so good for a female because she only needs to mate a few times to fertilise all her eggs.
In addition, too much sex can be costly for female burying beetles as it reduces their ability to provide parental care.
For the study, published in the journal Evolution, the researchers artificially selected pairs of burying beetles for either high mating rates or low rates for ten generations. The research found that this artificial selection resulted in changes in the shapes of both male and female genitalia.
"Our research demonstrates the general importance of conflicts of interest between males and females in helping to generate some of the biodiversity that we see in the natural world," Hopwood noted.
