Department of Ecology, Scottish Association for Marine Science, Oban, Argyll, Scotland.
PLoS One. 2012;7(8):e41243. doi: 10.1371/journal.pone.0041243. Epub 2012 Aug 1.
The trophic interactions of sea urchins are known to be the agents of phase shifts in benthic marine habitats such as tropical and temperate reefs. In temperate reefs, the grazing activity of sea urchins has been responsible for the destruction of kelp forests and the formation of 'urchin barrens', a rocky habitat dominated by crustose algae and encrusting invertebrates. Once formed, these urchin barrens can persist for decades. Trophic plasticity in the sea urchin may contribute to the stability and resilience of this alternate stable state by increasing diet breadth in sea urchins. This plasticity promotes ecological connectivity and weakens species interactions and so increases ecosystem stability. We test the hypothesis that sea urchins exhibit trophic plasticity using an approach that controls for other typically confounding environmental and genetic factors. To do this, we exposed a genetically homogenous population of sea urchins to two very different trophic environments over a period of two years. The sea urchins exhibited a wide degree of phenotypic trophic plasticity when exposed to contrasting trophic environments. The two populations developed differences in their gross morphology and the test microstructure. In addition, when challenged with unfamiliar prey, the response of each group was different. We show that sea urchins exhibit significant morphological and behavioural phenotypic plasticity independent of their environment or their nutritional status.
已知海胆的营养相互作用是海底栖息地（如热带和温带珊瑚礁）相移的原因。在温带珊瑚礁中，海胆的摄食活动导致了巨藻林的破坏，并形成了“海胆荒地”，这是一种以壳状藻类和附生无脊椎动物为主的多岩石栖息地。一旦形成，这些海胆荒地可以持续数十年。海胆的营养可塑性可能通过增加海胆的饮食广度，为这种替代稳定状态的稳定性和恢复力做出贡献。这种可塑性促进了生态连通性，减弱了物种间的相互作用，从而增加了生态系统的稳定性。我们使用一种可以控制其他通常会混淆的环境和遗传因素的方法来检验海胆表现出营养可塑性的假设。为此，我们在两年的时间里，将一个遗传上同质的海胆种群暴露在两种截然不同的营养环境中。当暴露在不同的营养环境中时，海胆表现出广泛的表型营养可塑性。这两个种群在总体形态和外壳微观结构上存在差异。此外，当受到不熟悉的猎物挑战时，两组的反应也不同。我们表明，海胆表现出显著的形态和行为表型可塑性，而不受其环境或营养状况的影响。
