Department of Biology, University of Florida, Gainesville, Florida, United States of America.
PLoS One. 2011 Jan 24;6(1):e16557. doi: 10.1371/journal.pone.0016557.
The relative energetic investment in reproduction between the sexes forms the basis of sexual selection and life history theories in evolutionary biology. It is often assumed that males invest considerably less in gametes than females, but quantifying the energetic cost of gamete production in both sexes has remained a difficult challenge. For a broad diversity of species (invertebrates, reptiles, amphibians, fishes, birds, and mammals), we compared the cost of gamete production between the sexes in terms of the investment in gonad tissue and the rate of gamete biomass production. Investment in gonad biomass was nearly proportional to body mass in both sexes, but gamete biomass production rate was approximately two to four orders of magnitude higher in females. In both males and females, gamete biomass production rate increased with organism mass as a power law, much like individual metabolic rate. This suggests that whole-organism energetics may act as a primary constraint on gamete production among species. Residual variation in sperm production rate was positively correlated with relative testes size. Together, these results suggest that understanding the heterogeneity in rates of gamete production among species requires joint consideration of the effects of gonad mass and metabolism.
在进化生物学中，两性之间相对的生殖能量投入构成了性选择和生活史理论的基础。通常认为，雄性在配子上的投入比雌性少得多，但量化两性配子生产的能量成本一直是一个具有挑战性的难题。对于广泛的物种多样性（无脊椎动物、爬行动物、两栖动物、鱼类、鸟类和哺乳动物），我们比较了两性之间在性腺组织投资和配子生物量生产速率方面的配子生产成本。两性的性腺生物量投资几乎与体重成正比，但雌性的配子生物量生产速率大约是雄性的两到四个数量级。在雄性和雌性中，配子生物量生产速率随着生物体质量呈幂律增加，与个体代谢率非常相似。这表明，整个生物体的能量可能是物种间配子生产的主要限制因素。精子生产速率的剩余变异与相对睾丸大小呈正相关。这些结果表明，要理解物种间配子生产速率的异质性，需要综合考虑性腺质量和代谢的影响。
