Efficient utilization of very dilute aquatic sperm: sperm competition may be more likely than sperm limitation when eggs are retained
Efficient utilization of very dilute aquatic sperm: sperm competition may be more likely than sperm limitation when eggs are retained
复制标题
有效利用非常稀的水生精子：当保留卵子时，精子竞争可能比精子限制更有可能
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
J. Bishop
中科院分区：
文献类型：
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作者：
A. J. Pemberton;R. Hughes;P. Manríquez;J. Bishop
Fertilization success may be severely limited in marine invertebrates that spawn both male and female gametes. In a diverse group of aquatic organisms only sperm are released, with sperm-egg fusion occurring at the mother. Here, we report fertilization kinetics data for two such ‘brooding’ or ‘spermcast’ species - representing each major clade of the animal kingdom. High levels of fertilization were achieved at sperm concentrations of two or three orders of magnitude lower than is common with broadcast spawning species. At a concentration of 100 sperm ml−1, fertilization rates of a bryozoan and colonial ascidian were near maximum, whereas most broadcast spawners would have displayed near complete reproductive failure. A further experiment looked at the rate of uptake of sperm under natural conditions. Results suggested that sperm released at ca. 0.9 m from an acting female could be collected at a rate of 3–12 times greater than the minimum required simply to avoid sperm limitation. Thus, evolutionary pressures on gametic and other reproductive characteristics of many species that release sperm but retain eggs may be quite different from those of broadcast spawners and may confer on the former an enhanced scope for sperm competition and female choice.
