英和和英

出典:『Wikipedia』 (2011/05/16 23:35 UTC 版)

英語による解説

引用

Sperm competition is competition between the sperm of two different males to fertilize an ovum. Since females have decided to engage in promiscuous mating to increase their chances in producing more viable offspring, competition has evolved. Mating with more than one mate has generated a situation known as sperm competition; the presence of sperm competition has led to an evolutionary response; a response that has caused males to develop adaptations to help them increase their chances in succeeding in reproductive success. Sperm competition can be categorized with offensive and defensive roles; these categories are known to work antagonistically. Males have evolved several tactics that help them allocate their sperm effectively; this is dependent on how severe the influence of sperm competition on a given population is and is considered sperm competition that is on the defensive side. Adaptations and tactics such as mate-guarding, mating plugs, and releasing of toxic seminal substances to reduce female re-mating tendencies have advanced over time. The offensive form of sperm competition occurs when another male attempts to ruin or interrupt the reproductive success of the defensive male.