Aussie battler's mind-blowing sex marathon

There is no stopping the male praying mantids of Sydney. Even after their heads have been chewed off by their female partners, these hardy insects continue to have sex for up to eight hours.

"It's pretty cool to watch," said a Macquarie University scientist, Katherine Barry, whose research has led to an explanation for how this extreme form of sexual cannibalism may have evolved in false garden mantids, Pseudomantis albofimbriata, a species common to suburbs including Sydney suburbs of Epping, Pymble and Turramurra.

In one of the first studies able to demonstrate this effect, she found the cannibalistic females put on weight and produced more eggs using the extra energy they got from a single meal of male meat.

"Sexual cannibalism can boost the reproductive output of the females by up to 40 per cent," Miss Barry said.