Females of the African P. caligata oviposit in streams on barkless driftwood and roots. The number of females landing on the oviposition sites correlates with the number of males and the number of ovipositing females. At noon with a high density of ovipositing females, 89% of the newly arriving females were nonmates. There were two arrival patterns of non-receptive females which decreased male interference. At sites with a high male density the temporal pattern of female arrivals was clumped. 66.1% of the approaching females landed within 30 s of other females. At small oviposition sites with two males present approaching females preferred situations where intensive territorial contests between the males occurred.