Sperm competition

Post copulatory competition, occurs when females mate with more than one male. Production of specialised sperm or more sperm. To defend against use mate guarding so they will be last one to mate with female. Use of nuptial gifts to entice longer mating higher chances of last mating. Females evolving post copulatory sperm selection to choose what sperm to use. Males evolving specialised mating structures such as scrubbers to remove other sperm. Or development of more pleasurable structures to increase mating duration. Sperm plugs not allowing other sperm to reach ova (common in reptiles and insects).