School of Biological Sciences & Oceans Institute, The University of Western Australia, Perth, WA 6009, Australia.
Smithsonian National Museum of Natural History, Washington, DC 20560, USA.
Proc Biol Sci. 2024 May;291(2023):20240239. doi: 10.1098/rspb.2024.0239. Epub 2024 May 29.
The ocean's midwater is a uniquely challenging yet predictable and simple visual environment. The need to see without being seen in this dim, open habitat has led to extraordinary visual adaptations. To understand these adaptations, we compared the morphological and functional differences between the eyes of three hyperiid amphipods-, and . Combining micro-CT data with computational modelling, we mapped visual field topography and predicted detection distances for visual targets viewed in different directions through mesopelagic depths. 's eyes provide a wide visual field optimized for spatial vision over short distances, while 's and 's eyes have the potential to achieve greater sensitivity and longer detection distances using spatial summation. These improvements come at the cost of smaller visual fields, but this loss is compensated for by a second pair of eyes in and by behaviour in . The need to improve sensitivity while minimizing visible eye size to maintain crypsis has likely driven the evolution of hyperiid eye diversity. Our results provide an integrative look at how these elusive animals have adapted to the unique visual challenges of the mesopelagic.
海洋中层是一个独特的具有挑战性但可预测和简单的视觉环境。在这个昏暗、开放的栖息地中，需要在不被发现的情况下进行观察，这导致了非凡的视觉适应。为了理解这些适应，我们比较了三种 hyperiid 桡足类动物——、和的眼睛的形态和功能差异。我们结合微 CT 数据和计算模型，绘制了通过中层水深从不同方向观察到的视场地形，并预测了视觉目标的检测距离。的眼睛提供了一个优化的宽视场，用于短距离的空间视觉，而和的眼睛有可能通过空间总和实现更高的灵敏度和更长的检测距离。这些改进是以较小的视场为代价的，但通过在和中第二对眼睛以及行为可以弥补这种损失。在保持伪装的同时提高灵敏度而最小化可见眼睛大小的需求可能推动了 hyperiid 眼睛多样性的进化。我们的研究结果综合了这些难以捉摸的动物如何适应中层独特的视觉挑战的情况。
