Inducible chemical defenses are more common in temperate seaweeds than tropical ones, and are directly detected by increase of chemical contents, or indirectly by differential consumption of live seaweed tissues or artificial food with algal extracts by herbivores. In general, seaweed-induced chemical defense occur between 11 and 20 days after both simulated/artificial or direct herbivory. Here, we used experimental procedures to assess induced chemical defense in the tropical red seaweed Laurencia dendroidea as response to direct grazing, chemical cues from grazed conspecific neighbors and only presence of herbivores. Chemical defenses were analyzed by detecting the palatability of artificial food containing L. dendroidea extracts offered to Aplysia brasiliana and by comparative analyses of extracts from this seaweed by Gas Chromatography/Mass Spectroscopy, as well as metabolomic data analysis by Principal Component Analysis. Our results revealed that direct grazing by A. brasiliana induced a rapid (after 48 h) response among individuals of L. dendroidea, as did waterborne chemical cues from grazed conspecifics, but the presence of sea hare alone did not elicit a response. Increased resistance to grazing was accompanied by significative changes in sesquiterpene metabolomic chemical profile, revealing that induced defense: may be more widespread among seaweeds, independent of latitude; can involve changes in other classes of substances besides phlorotannins or not only the increase in the content of a single compound; and may be a rapid and ecologically coherent response to consumers. In addition, the importance of incorporating the metabolomic approach when examining inducible chemical defense in seaweeds is also emphasized.

在温带海藻中，可诱导的化学防御比热带海藻更常见，并且可以通过化学含量的增加直接检测到，或者通过食草动物的藻类提取物对活海藻组织或人造食物的不同消耗而间接检测到。通常，海藻诱导的化学防御发生在模拟/人工或直接食草后的11至20天之间。在这里，我们使用实验程序来评估热带红海藻Laurencia dendroidea中诱导的化学防御反应，这是对直接放牧，放牧同种邻居的化学提示以及仅草食动物的反应。通过检测提供给巴西海ly的含有树突孢菌提取物的人造食品的适口性来分析化学防御作用并通过气相色谱/质谱法对该海藻提取物进行比较分析，以及通过主成分分析进行代谢组学数据分析。我们的研究结果表明，巴西放牧假单胞菌的直接放牧引起了L. dendroidea个体的快速反应（48小时后），和来自放牧特定物种的水性化学线索一样，但仅海兔的存在并没有引起反应。对放牧的抵抗力增强，同时倍半萜代谢组学化学特征发生显着变化，这表明诱导的防御作用：可能在海藻中更普遍，不受纬度的影响。可能会涉及除螺菌丹宁以外的其他种类物质的变化，或不仅涉及单一化合物含量的增加；并且可能是对消费者的快速且生态一致的反应。此外，还强调了在研究海藻中可诱导的化学防御时纳入代谢组学方法的重要性。