School of Marine Science and Policy, College of Earth, Ocean and Environment, University of Delaware, 700 Pilottown Road, Lewes, Delaware, 19958, USA.
Ecology. 2017 Aug;98(8):1989-1995. doi: 10.1002/ecy.1899. Epub 2017 Jul 6.
Specialized defense strategies are induced in zooplankton upon detection of predator chemical cues or kairomones. These defenses are well-described for freshwater zooplankters, with morphological defenses being particularly striking, but few studies have reported kairomone-induced morphological defenses in marine zooplankton. Here, we compare morphological responses to kairomones in the larvae of two marine crab species, estuarine mud crabs (Rhithropanopeus harrisii) and Asian shore crabs (Hemigrapsus sanguineus). When reared in the presence of fish kairomones, spine length increased by 2-3% in larval R. harrisii, while no morphological changes were identified in H. sanguineus. In subsequent feeding assays with a co-occurring fish predator (Atlantic silversides, Menidia menidia), consumption of R. harrisii was lower on larvae that had been reared with kairomones. In addition, we found that broods with smaller larvae are more likely to exhibit increases in spine length after kairomone exposure. Hence, the observed morphological response is likely influenced by larval size.
当浮游动物检测到捕食者的化学信号或化感物质时，就会产生专门的防御策略。这些防御策略在淡水浮游动物中得到了很好的描述，形态防御尤其引人注目，但很少有研究报道过海洋浮游动物对化感物质的形态防御。在这里，我们比较了两种海洋蟹类（河口泥蟹和亚洲滨蟹）幼虫对化感物质的形态反应。当在鱼类化感物质存在的情况下饲养时，幼虫 R. harrisii 的刺长度增加了 2-3%，而 H. sanguineus 则没有发现形态变化。在随后的与共同出现的鱼类捕食者（大西洋鲱鱼，Menidia menidia）的摄食实验中，在有化感物质饲养的幼虫中，R. harrisii 的摄食量较低。此外，我们发现，在化感物质暴露后，体型较小的幼虫的刺长度增加的可能性更大。因此，观察到的形态反应可能受到幼虫大小的影响。
