Penn D, Brockmann H J
Biol Bull. 1994 Dec;187(3):373-384. doi: 10.2307/1542294.
Like a number of other species, horseshoe crabs lay their eggs on beaches in the intertidal zone. The elevation of the beach on which they nest differs among populations. We examined two factors that potentially affect egg survival at different beach elevations: erosion and rate of development. We found no evidence that eggs buried at different elevations incur different risks of erosion by wave action. However, the optimal beach elevation for egg development differed between our two study sites, Florida and Delaware, and the difference was related to beach morphology. Rate of development increased with oxygen concentration, redox potential, and temperature, and all three of these factors changed with elevation. The nests in the lower beach failed to develop, especially in Florida, where the beach was fine-grained and poorly drained. The nests in the upper beach were prone to dessication, especially in Delaware, where the beach was course-grained and well-drained. This means that differencces between sites in the optimal location for egg development coincided with horseshoe crab preferences in nestsite selection. We suggest that horseshoe crabs synchronize their nesting with the tides that reach the aerobic sediments on the beach, resulting in nesting patterns that differ with differences in tidal regimes and beach morphology.
与许多其他物种一样，鲎在潮间带的海滩上产卵。它们筑巢的海滩海拔高度因种群而异。我们研究了两个可能影响不同海滩海拔高度卵存活率的因素：侵蚀和发育速度。我们没有发现证据表明埋在不同海拔高度的卵遭受波浪作用侵蚀的风险不同。然而，我们的两个研究地点——佛罗里达州和特拉华州——卵发育的最佳海滩海拔高度不同，且这种差异与海滩形态有关。发育速度随氧气浓度、氧化还原电位和温度的升高而增加，而这三个因素都随海拔高度而变化。较低海滩的巢穴无法发育，尤其是在佛罗里达州，那里的海滩细颗粒且排水不良。较高海滩的巢穴容易干燥，尤其是在特拉华州，那里的海滩粗颗粒且排水良好。这意味着卵发育最佳位置的地点差异与鲎在巢穴选址上的偏好相吻合。我们认为，鲎会根据到达海滩上需氧沉积物的潮汐来同步它们的筑巢时间，从而导致筑巢模式因潮汐状况和海滩形态的差异而有所不同。
