In sexually cannibalistic spiders, males usually only copulate with one female. This selects for male strategies to improve paternity success in their single mate. Male mating strategies can include genital damage during female attack in some cannibalistic orb-weaving spiders, where males are dwarf and females polyandrous. We explored whether sexual cannibalism is necessary for male genital damage in the silver spider Argiope argentata (Fabricius 1775) by performing mating trials with recently killed virgin females. We found that males can break off their copulatory organs without female intervention and spontaneously die during copulation. Results suggest that genital damage evolved in response to sperm competition in this species.