I thought these spiders were fighting over possession of a web, but someone more knowledgeable on these matters has suggested that they are mating.

The larger spider is a Golden Orb Weaver, apparently a female, and the other is the male G.O.W. Events were taking place about 3 metres from the ground.

D200 manual 1/60 f11, SB800 manual 1/4, lens Nikon 105 macro.