Spady Blake L, Watson Sue-Ann
Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, Australia.
College of Science and Engineering, James Cook University, Townsville, QLD, Australia.
PeerJ. 2020 Sep 29;8:e9865. doi: 10.7717/peerj.9865. eCollection 2020.
Anthropogenic carbon dioxide (CO) emissions are being absorbed by the oceans, a process known as ocean acidification, and risks adversely affecting a variety of behaviours in a range of marine species, including inhibited learning in some fishes. However, the effects of elevated CO on learning in advanced invertebrates such as cephalopods are unknown. Any impacts to the learning abilities of cephalopods could have far-reaching consequences for their populations and the communities they inhabit. Cephalopods have some of the most advanced cognitive abilities among invertebrates and are one of the few invertebrate taxa in which conditional discrimination has been demonstrated, though the trait has not been demonstrated in any species of squid. Here, we tested for the first time the capacity for conditional discrimination in a squid species (). Furthermore, we investigated the effects of projected future CO levels (1,084 µatm) on conditional discrimination and learning more generally. A three-task experiment within a two-choice arena was used to test learning and conditional discrimination. Learning was measured by improvements in task completion in repeated trials over time and the number of trials required to pass each task. Squid exhibited significant learning capabilities, with an increase in correct choices over successive trials and a decrease in the number of trials needed to complete the successive tasks. Six of the 12 squid tested successfully passed all three tasks indicating a capacity for conditional discrimination in the species. Elevated CO had no effect on learning or on the capacity for conditional discrimination in squid. This study highlights the remarkable cognitive abilities of , demonstrated by their capacity for conditional discrimination, and suggests that ocean acidification will not compromise learning abilities. However, other behavioural traits in the species have been shown to be altered at comparable elevated CO conditions. It is not clear why some ecologically important behaviours are altered by elevated CO whereas others are unaffected. Future research should focus on the physiological mechanism responsible for altered behaviours in squid at elevated CO.
人为二氧化碳（CO）排放正被海洋吸收，这一过程被称为海洋酸化，它有可能对一系列海洋物种的多种行为产生不利影响，包括抑制某些鱼类的学习能力。然而，二氧化碳浓度升高对诸如头足类动物等高等无脊椎动物学习的影响尚不清楚。对头足类动物学习能力的任何影响都可能对其种群及其栖息的群落产生深远后果。头足类动物具有无脊椎动物中一些最先进的认知能力，是少数已证明具有条件性辨别能力的无脊椎动物类群之一，不过在任何鱿鱼物种中尚未证明这一特性。在此，我们首次测试了一种鱿鱼物种（）的条件性辨别能力。此外，我们更广泛地研究了预计未来二氧化碳水平（1084微大气压）对条件性辨别和学习的影响。在一个二选一的场地内进行了一个三任务实验来测试学习和条件性辨别能力。通过随着时间推移在重复试验中任务完成情况的改善以及完成每个任务所需的试验次数来衡量学习情况。鱿鱼表现出显著的学习能力，在连续试验中正确选择次数增加，完成连续任务所需的试验次数减少。测试的12只鱿鱼中有6只成功通过了所有三项任务，表明该物种具有条件性辨别能力。二氧化碳浓度升高对鱿鱼的学习能力或条件性辨别能力没有影响。这项研究突出了（鱿鱼）卓越的认知能力，这体现在它们的条件性辨别能力上，并表明海洋酸化不会损害学习能力。然而，在类似的高二氧化碳条件下，该物种的其他行为特征已被证明会发生改变。目前尚不清楚为什么某些具有生态重要性的行为会因二氧化碳浓度升高而改变，而其他行为则不受影响。未来的研究应聚焦于导致鱿鱼在高二氧化碳环境下行为改变的生理机制。
