Does male reproductive effort increase with age? Courtship in fiddler crabs
Does male reproductive effort increase with age? Courtship in fiddler crabs
复制标题
男性的生育努力会随着年龄的增长而增加吗？
作者：
Catherine L. Hayes;I. Booksmythe;M. Jennions;P. Backwell
理论表明，生殖努力通常会随着年龄的增长而增加，但生活史模型表明其他结果也是可能的。需要经验数据来量化实际年龄依赖性的变化。雌性的数据很容易获得（例如每枚卵的窝数），但雄性的数据却很难获得（例如求偶努力）。要量化男性的努力，必须：（一）实验控制潜在的年龄依赖性变化，女性的存在;和，至关重要的是，（二）区分求爱的可能性被启动，显示率，和总时间投资在求爱前停止（“求爱持久性”）。我们提供了一个简单的实验协议，适用于许多类群，以说明如何获得这些信息。我们研究了雄性招潮蟹的求偶招手。由于不确定的增长，身体大小与年龄相关。体型较大的雄性更有可能向雌性挥手，而且挥手更持久。然而，它们并没有更高的求偶率（每秒波数）。一个已知的女性偏好男性具有较高的显示率解释了为什么，一旦挥手开始，所有的男性显示在相同的速度。
Theory suggests that reproductive effort generally increases with age, but life-history models indicate that other outcomes are possible. Empirical data are needed to quantify variation in actual age-dependence. Data are readily attainable for females (e.g. clutch per egg size), but not for males (e.g. courtship effort). To quantify male effort one must: (i) experimentally control for potential age-dependent changes in female presence; and, crucially, (ii) distinguish between the likelihood of courtship being initiated, the display rate, and the total time invested in courting before stopping (‘courtship persistence’). We provide a simple experimental protocol, suitable for many taxa, to illustrate how to obtain this information. We studied courtship waving by male fiddler crabs, Uca annulipes. Given indeterminate growth, body size is correlated with age. Larger males were more likely to wave at females and waved more persistently. They did not, however, have a higher courtship rate (waves per second). A known female preference for males with higher display rates explains why, once waving is initiated, all males display at the same rate.