 P. labiata females are extremely aggressive to other females , trying to invade and take over each other 's webs , which often results in cannibalism . A laboratory test showed how they minimise the risk of meeting each other , by recognising pieces with blotting paper containing their own silk draglines and pieces contain other P. labiata females ' draglines . If obstacles make it impossible to see whether the other is physically present , she avoids blotting paper containing the other 's draglines , but moves with no constraint if she can see that the other female is not around . Draglines seem to act as territory marks , much as many mammals identify conspecifics by scent marking . P. labiata females also avoid rival females of higher fighting ability and spend more time around less powerful fighters . A laboratory test collected samples of the draglines of equal @-@ sized females and then pitted some of them in contests . Other females avoided the draglines of the victors , and spent the majority of their time on draglines of the losers . Similar tests showed that females of P. fimbriata from Australia and P. schultzi from Kenya do not avoid draglines of a powerful fighter . : 753 
