Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ 08901;
Physics Department, Skidmore College, Saratoga Springs, NY 12866.
Proc Natl Acad Sci U S A. 2018 Aug 7;115(32):E7532-E7540. doi: 10.1073/pnas.1804558115. Epub 2018 Jul 23.
Marine population dynamics often depend on dispersal of larvae with infinitesimal odds of survival, creating selective pressure for larval behaviors that enhance transport to suitable habitats. One intriguing possibility is that larvae navigate using physical signals dominating their natal environments. We tested whether flow-induced larval behaviors vary with adults' physical environments, using congeneric snail larvae from the wavy continental shelf () and from turbulent inlets (). Turbulence and flow rotation (vorticity) induced both species to swim more energetically and descend more frequently. Accelerations, the strongest signal from waves, induced a dramatic response in but almost no response in competent Early stage did react to accelerations, ruling out differences in sensory capacities. Larvae likely distinguished turbulent vortices from wave oscillations using statocysts. Statocysts' ability to sense acceleration would also enable detection of low-frequency sound from wind and waves. potentially hear and react to waves that provide a clear signal over the continental shelf, whereas effectively "go deaf" to wave motions that are weak in inlets. Their contrasting responses to waves would cause these larvae to move in opposite directions in the water columns of their respective adult habitats. Simulations showed that the congeners' transport patterns would diverge over the shelf, potentially reinforcing the separate biogeographic ranges of these otherwise similar species. Responses to turbulence could enhance settlement but are unlikely to aid large-scale navigation, whereas shelf species' responses to waves may aid retention over the shelf via Stokes drift.
海洋种群动态通常取决于幼虫的扩散，而幼虫存活的机会微乎其微，这就形成了对增强幼虫向适宜栖息地运输能力的行为的选择性压力。一种有趣的可能性是，幼虫利用主导其出生地环境的物理信号进行导航。我们通过来自波状大陆架（）和湍流入口（）的同属蜗牛幼虫来测试幼虫的行为是否随成虫的物理环境而变化。湍流和流动旋转（涡度）诱导这两个物种更积极地游动和更频繁地下降。加速度是波浪发出的最强信号，导致 种幼虫剧烈反应，但在有能力的 种幼虫中几乎没有反应。早期阶段的 幼虫确实对加速度做出了反应，排除了感觉能力的差异。幼虫可能使用平衡囊来区分湍流涡旋和波浪振荡。平衡囊感知加速度的能力还可以检测到风和波浪产生的低频声音。 幼虫可能会听到并对在大陆架上提供清晰信号的波浪做出反应，而 幼虫在入口处的弱波浪运动中则“失聪”。它们对波浪的反应相反，这将导致这些幼虫在各自成年栖息地的水柱中向相反的方向移动。模拟表明，这两种同属幼虫的运输模式将在大陆架上出现分歧，这可能会加强这些原本相似的物种的独立生物地理范围。对湍流的反应可以增强定居，但不太可能有助于大规模导航，而对波浪的反应可能会通过斯托克斯漂移帮助幼虫在大陆架上停留。
