Advice on how to score with the ladies would probably never include the strategy that works best for at least one species of male spider: playing dead.

Not all male nursery web spiders looking for a little arachnid sex adopt this technique, but those that do more than double their chances of hitting the jackpot, according to new study in Behavioral Ecology, reported Wednesday in the British magazine New Scientist.

In experiments designed by Trine Bilde of the University of Aaarhus in Denmark, researchers set up date-and-mate opportunities for Pisaura mirabilis, a species native to Europe.

All the males sought to attract partners by offering a gift of food, held in the mouth.

But the ones that lay flat and motionless -- even if meant getting dragged about by a female that had latched onto the victuals -- wound up in a much better position, as it were, to engage in sexual activity.

The hapless males that tried the direct approach wound up keeping the free meal but not getting what they were really after.

Males that played dead were also allowed to copulate longer than males that did not, ensuring more eggs could fertilized, the researchers reported.

Playing dead is a well-known defence mechanism in nature, but this is apparently the first time such behaviour has been observed as a strategy for obtaining sexual favours.

While it only turns into a handsome prince in fairy tales, the homely bullfrog may harbour a valuable anti-ageing substance for humans, South Korean researchers say.

A team led by Professor Kim Se-kwon of Pukyong University in Busan says it isolated a peptide with antioxidant properties from bullfrog skin.

Because of the properties, the material is useful in removing free radicals -- molecules that hasten the ageing process of human cells.

Alpha-tocopherol, also known as Vitamin E, is traditionally considered as the most active antioxidant in humans and widely used in medicines and health supplements.

But its price keeps rising because of surging world demand.

"The new sustance can provide an economic alternative to tocopherol," Kim told AFP Tuesday, referring to another antioxidant. The team's discovery was published by Bioresource Technology, an international journal, last year.

"Because it is water-soluble, the substance may be consumed in much more diverse ways than the oil-soluble tocopherol. You may put it in soft drinks, for example," he said.

The newly found material is also 10 percent more efficient than tocopherol in curbing oxidisation, he added.