Sperm competition is a term used to refer to the competitive process between
spermatozoa of two or more different males to
fertilize the same
egg during
sexual reproduction. Competition can occur when females have multiple potential mating partners. Greater choice and variety of mates increases a female's chance to produce more viable offspring. However, multiple mates for a female means an individual male has decreased chances of producing offspring. Sperm competition is an evolutionary pressure on males, and has led to the development of adaptations to increase males' chance of
reproductive success. Sperm competition results in a
sexual conflict of interest between males and females. Males have evolved several defensive tactics including: mate-guarding,
mating plugs, and releasing toxic seminal substances to reduce female re-mating tendencies to cope with sperm competition. Offensive tactics of sperm competition involve direct interference by one male on the reproductive success of another male, for instance by physically removing another male's sperm prior to mating with a female. For an example, see
Gryllus bimaculatus.