Amodio Piero, Fiorito Graziano
Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Napoli, Italy.
Front Physiol. 2022 Aug 30;13:951808. doi: 10.3389/fphys.2022.951808. eCollection 2022.
Mirror self-recognition (MSR) is a potential indicator of self-awareness. This capability has been widely investigated among vertebrates, yet it remains largely unstudied in invertebrates. Here we report preliminary data about behavioural responses exhibited by common octopuses () toward reflected images of themselves and explore a procedure for marking octopus' skin in order to conduct the Mark test. Octopuses ( = 8) received four familiarization trials with a mirror and four familiarization trials with a control stimulus: a non-reflective panel ( group, = 4) or the sight of a conspecific housed in an adjacent tank ( group, = 4). Subsequently, octopuses were marked with non-toxic nail polish in the area where the Frontal White Spots are usually expressed, and they received one test trial with the mirror and one control trial with no mirror. We found that octopuses in the group tended to exhibit a stronger exploratory response toward the mirror than the non-reflective panel, but performed agonistic responses only in the presence of the mirror. In contrast, octopuses in the group exhibited comparable exploratory and agonistic behaviours toward the mirror and the sight of the conspecific. In the Mark test, octopuses frequently explored the mark their arms. However, mark-directed behaviours were also observed in the absence of the mirror and in sham-marked individuals, thus suggesting that proprioceptive stimuli drove these responses. Despite the limitations associated with our marking procedure, the baseline data collected in this pilot study may facilitate the further testing of MSR in the octopus and other cephalopods.
镜像自我识别（MSR）是自我意识的一个潜在指标。这种能力在脊椎动物中已得到广泛研究，但在无脊椎动物中仍基本未被研究。在此，我们报告关于普通章鱼对自身反射图像所表现出的行为反应的初步数据，并探索一种给章鱼皮肤做标记的方法，以便进行标记测试。章鱼（n = 8）接受了四次使用镜子的熟悉试验和四次使用对照刺激的熟悉试验：一个非反射面板（A组，n = 4）或看到相邻水箱中的同种个体（B组，n = 4）。随后，在通常出现额白斑的区域用无毒指甲油给章鱼做标记，然后它们接受一次使用镜子的测试试验和一次不使用镜子的对照试验。我们发现，A组的章鱼对镜子表现出的探索反应往往比非反射面板更强，但仅在有镜子时表现出攻击反应。相比之下，B组的章鱼对镜子和看到同种个体表现出类似的探索和攻击行为。在标记测试中，章鱼频繁地用它们的触手探索标记。然而，在没有镜子的情况下以及在假标记个体中也观察到了针对标记的行为，因此表明本体感觉刺激驱动了这些反应。尽管我们的标记方法存在局限性，但在这项初步研究中收集的基线数据可能有助于进一步测试章鱼和其他头足类动物的镜像自我识别能力。
