Warner R R, Shapiro D Y, Marcanato A, Petersen C W
Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara 93106, USA.
Proc Biol Sci. 1995 Nov 22;262(1364):135-9. doi: 10.1098/rspb.1995.0187.
In natural populations of a coral reef fish (the bluehead wrasse, Thalassoma bifasciatum), males with the highest daily mating success produce the fewest sperm per mating, and this is reflected in significantly lower fertilization rates. The average amount released by males in pair-mating was 3.3 x 10(6) spermatozoa, resulting in a fertilization rate of 96%. Sperm released per spawn declined with increasing mating success, so that females mating with the most successful males had less than 93% of their eggs fertilized. It is unlikely that high mating-success males are physiologically incapable of increasing sperm production, because younger males with different mating strategies have absolutely larger testes and higher daily sperm output. Feeding experiments suggest that high-success males are diverting energy from gamete production to other fitness-enhancing activities such as mate guarding. Females incur the cost of low sperm release by having fewer of their eggs fertilized. There are no obvious compensatory benefits to females from mating with high-success males.
在一种珊瑚礁鱼类（双带锦鱼，Thalassoma bifasciatum）的自然种群中，每日交配成功率最高的雄性每次交配产生的精子数量最少，这体现在受精率显著较低上。在成对交配中，雄性释放的平均精子数量为3.3×10⁶个，受精率为96%。每次产卵释放的精子数量随着交配成功率的增加而减少，因此与最成功的雄性交配的雌性，其卵子的受精率不到93%。交配成功率高的雄性在生理上不太可能无法增加精子产量，因为具有不同交配策略的年轻雄性拥有绝对更大的睾丸和更高的每日精子产量。喂养实验表明，交配成功率高的雄性正在将能量从配子生产转移到其他提高适应性的活动上，比如守护配偶。雌性因精子释放量低而付出代价，其卵子受精的数量减少。雌性与交配成功率高的雄性交配并没有明显的补偿性益处。
