In the present study, we evaluated the trophic role of Octopus insularis Leite and Haimovici 2008 in the food web of Rocas Atoll, a preserved insular territory in the Southwest Atlantic. Using stable isotope analysis of C and N, we showed that the local trophic web comprises at least four trophic levels, where the octopus occupies a trophic position (TP) between the second and third trophic levels (mean ± SD TP_additive = 3.08 ± 0.36; TP_Bayesian = 3.12 ± 0.17). Among other benthic/reef-associated consumers, this cephalopod stood out for its much wider isotopic niche, pointing to a diet diversified in carbon sources, but focussed on prey in lower TPs. This finding was in accordance with the time-minimizing feeding strategy described for the species, which seemed almost permanent throughout the life cycle of the octopus, given the great niche overlap between octopuses in different maturity stages and their very similar trophic positions. Also, as a prey, octopuses composed up to almost 23% of the diet of some benthic/demersal predators. Overall, O. insularis represented an important mesopredator for the local food web, principally for bottom-associated organisms, while also serving as a substantial energy input to the next trophic levels.

在本研究中，我们评估了Octopus insularis Leite 和 Haimovici 2008 在罗卡斯环礁食物网中的营养作用，罗卡斯环礁是西南大西洋保存完好的岛屿领土。使用C和N 的稳定同位素分析，我们表明局部营养网至少包含四个营养级，其中章鱼占据第二和第三营养级之间的营养位置 (TP)（平均值±SD TP_添加剂 = 3.08 ± 0.36 ; TP_贝叶斯 = 3.12 ± 0.17)。在其他底栖/珊瑚礁相关消费者中，这种头足类动物因其更广泛的同位素生态位而脱颖而出，表明其饮食碳源多样化，但专注于较低 TP 的猎物。这一发现与为该物种描述的时间最小化喂养策略一致，考虑到不同成熟阶段的章鱼之间的生态位重叠及其非常相似的营养位置，这似乎在章鱼的整个生命周期中几乎是永久性的。此外，作为猎物，章鱼占某些底栖/底层捕食者饮食的近 23%。总体而言，O. insularis代表了当地食物网的重要中掠食者，主要是底层相关生物，同时也为下一个营养级别提供了大量的能量输入。