To keep cranky females happy, their partners have to spend about 100 minutes on courtship, doing things such as vibrating their webs and rubbing their tummies.
But once the fickle babes are brought to a peak of amorous and receptive behaviour, they will let a stray male mate with them even if he hasn't done any courting at all.
(Thanks to Ralph)
In other spider-sex news, we have this.
(Thanks to Rafi Farber)
And in vaguely related alarming spider news, we have this.
(Thanks to Siouxie, Andy Walker and PhilB)