Should I stay or should I go: predator- and conspecific-induced hatching in a marine snail
Should I stay or should I go: predator- and conspecific-induced hatching in a marine snail
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我应该留下还是应该离开：捕食者和同种诱导的海洋蜗牛孵化
作者：
B. Miner;D. Donovan;K. E. Andrews
捕食者诱导的孵化可塑性已在许多两栖动物物种中得到证实。然而，来自其他分支的动物（例如，海洋物种的软体动物和环节动物）也将它们的胚胎放在胶囊或凝胶状物质中，并且也可能对捕食者表现出孵化可塑性。到目前为止，没有证据表明捕食者诱导的孵化可塑性从任何海洋物种或一个主要的分支的bilateria动物，Lophotrochozoa。我们研究了捕食者诱导的孵化可塑性Nucella lamellosa，一种肉食性的海洋蜗牛，在胶囊中沉积胚胎。我们用两个实验来研究两种类型的捕食者，螃蟹和等足类动物，对胚胎发育的影响。在第一个实验中，我们通过暴露于螃蟹和等足类动物的水传播化学物质的时间来量化胶囊中孵化胚胎的比例。螃蟹延迟孵化时间，捕食者的影响是累加的。在第二个实验中，我们通过时间，发育阶段，和胶囊中的胚胎暴露于水传播的化学品的螃蟹和同种胶囊孵化胚胎的比例进行了量化。通过这个实验，我们想回答：（1）孵化延迟是否与胚胎发育较慢相对应，以及（2）生物体代谢废物的一般产物是否会延迟孵化。我们出乎意料地观察到，成年同种蜗牛加速孵化，但不是发展速度-少数过去的研究同种的影响都表明，同种延迟孵化时间和发展速度。结果也不一致的代谢废物一般造成孵化延迟，虽然同种的影响确实削弱了这一推论。这项研究表明，捕食者延迟时间孵化的海洋软体动物，并表明，捕食者诱导的孵化可塑性是广泛的动物和可能进化多次内的双边。此外，同种加快了海洋软体动物的孵化时间，这表明同种，像捕食者，可能会影响胚胎孵化的时间。
Predator-induced hatching plasticity has been demonstrated in many species of amphibians. However, animals from other clades (e.g., marine species of molluscs and annelids) also place their embryos in capsules or gelatinous masses and might also exhibit hatching plasticity to predators. To date there is no evidence of predator-induced hatching plasticity from any marine species or a major clade of bilateria animals, the Lophotrochozoa. We studied predator-induced hatching plasticity of Nucella lamellosa, a carnivorous marine snail that deposits embryos in capsules. We used two experiments to investigate the effects of two types of predator, crabs and isopods, on developing embryos. In the first experiment, we quantified proportion of hatched embryos from capsules through time exposed to water-borne chemicals of crabs and isopods. Crabs delayed time-to-hatching, and the effects of predators were additive. In the second experiment, we quantified proportion of hatched embryos from capsules through time, developmental stage, and size of embryos in capsules exposed to water-borne chemicals of crabs and conspecifics. With this experiment, we wanted to answer: (1) whether a delay in hatching corresponded to embryos developing slower, and (2) whether the general products of metabolic waste from organisms can delay hatching. We unexpectedly observed that adult conspecific snails accelerated hatching but not developmental rate—the few past studies on the effects of conspecifics have all demonstrated that conspecifics delay time-to-hatching and rate of development. The results were also inconsistent with metabolic waste in general causing a delay in hatching, although the effect of conspecifics does weaken this inference. This study demonstrates that predators delay time-to-hatching in a marine mollusc, and suggests that predator-induced hatching plasticity is widespread among animals and likely evolved multiple times within the bilateria. In addition, conspecifics accelerated time-to-hatching in a marine mollusc, which suggests that conspecifics, like predators, might commonly influence when embryos hatch.