Redback females are, like most spiders, promiscuous. Sperm competition means that mating does not guarantee fertilization. So for a male, dying after sex may be no different to dying before sex, if the female goes on to mate again. In the case of the redback, cannibalized males receive two paternity advantages. First, it seems they copulate for longer, which leads to their fertilizing more eggs than males that survived. Second, females were more likely to reject subsequent suitors after consuming their first mate. They were well and truly sated. Given that 80 per cent of redback males will
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