Octopus insularis is an active and opportunistic predator, its diet depends on the habitat in which it develops and the abundance and distribution of the species it preys on. Despite its importance for fisheries, little is known about the trophic relationships of this octopus. For this reason, the main objective of this study was to describe its diet in the southern Gulf of Mexico combining stable δ¹³C and δ¹⁵N isotopes and stomach content analysis. Stable δ¹³C and δ¹⁵N isotope analysis were performed in muscle tissue of octopuses and their prey. In addition, stomachs were analyzed to identify consumed prey and to obtain percentages of numerical and gravimetric importance, the frequency of occurrence and the index of relative importance. The diet did not show differences between year, sex, or size. Eight crustacean and three fish genera were identified as the main components in the diet. Crustaceans appeared as the main prey group, and the most important prey within this group was Mithraculus sp., and for the fish group it was Anchoa sp. The isotope analysis indicates a high contribution to predator´s muscle tissue from both crustaceans and fish. In one hand, results indicate that crustaceans as prey are important for the octopus population in the whole distribution area. On the other hand, isotope values positioned O. insularis as an intermediate trophic level predator, placing it as an efficient vehicle of energy transfer between lower to higher trophic levels in the ecosystem.

章鱼是一种活跃且机会主义的捕食者，其饮食取决于它在其中生长的栖息地以及它所捕食的物种的丰富和分布。尽管它对渔业很重要，但对这种章鱼的营养关系知之甚少。出于这个原因，主要目的本研究是描述在墨西哥湾南部的稳定相结合的饮食δ ¹³ C和δ ^15个ñ同位素和胃内容分析。稳定δ ¹³ C和δ ¹⁵在章鱼及其猎物的肌肉组织中进行了N同位素分析。此外，还对胃进行了分析，以确定消耗的猎物，并获得数值和重量重要性百分比，出现频率和相对重要性指数。饮食在年，性别或大小之间没有差异。饮食中的主要成分被确定为八个甲壳类和三个鱼类。甲壳类动物出现为主要猎物组，该组中最重要的猎物是Mithraculus属，为鱼组为Anchoasp。同位素分析表明甲壳动物和鱼类对捕食者的肌肉组织都有很大贡献。一方面，结果表明甲壳类动物是整个分布区域中章鱼种群的重要猎物。另一方面，同位素值将海岛稻（O. insularis）定位为营养级中间的捕食者，使其成为生态系统中较低营养级到较高营养级之间能量转移的有效工具。