In the Colombian orb-web spider Leucauge mariana (Taczanowski, 1881) (Tetragnathidae), both sexes contribute to mating plug formation. Males of this species show a conductor hook that could be involved in providing stability to the mating pair and used for mating plug removal. The aim of the study was to assess the relationship between the shape of the conductor hook in L. mariana and mating duration, the amount of sperm stored, and the occurrence of sexual cannibalism. We used geometric morphometric tools for studying the conductor hook shape. The width of the base of the conductor hook was negatively correlated with the probability of sexual cannibalism by females (PC2 = 0.017), but we did not find a significant relation with mating duration and the amount of sperm transferred. Female choice on male hook shape, or on the stability provided by the hook during the mating position, could be occurring in this species.