Two eyes for two purposes: in situ evidence for asymmetric vision in the cockeyed squids Histioteuthis heteropsis and Stigmatoteuthis dofleini
Two eyes for two purposes: in situ evidence for asymmetric vision in the cockeyed squids Histioteuthis heteropsis and Stigmatoteuthis dofleini
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两只眼睛有两个目的：斜眼鱿鱼 Histioteuthis heropsis 和 Stigmatoteuthis dofleini 视觉不对称的现场证据
DOI：
10.1098/rstb.2016.0069
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
S. Johnsen
中科院分区：
文献类型：
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作者：
Kate N. Thomas;B. Robison;S. Johnsen
海洋中层区域的光环境随着深度和观看者方向的变化而变化，这可能推动了其居民视觉适应的高度多样性。组织科中层“斜眼”鱿鱼的眼睛不寻常，因为左右眼的大小、形状和有时晶状体色素沉着都不同。这种二态性可能是对中层区域两种不同光源的适应，大眼睛向上观看在昏暗、下降的阳光下观察物体的轮廓，而小眼睛稍微向下观看生物发光点源。我们使用蒙特利海底峡谷遥控车辆的现场视频片段来观察 152 只 Stigmatoteuthis heropsis 和 9 只 Stigmatoteuthis dofleini 的定向行为。我们发现了大眼睛向上定向和小眼睛略微向下定向的证据，这是由尾部向上倾斜的身体定向促进的。我们还发现，65% 的成年异形异体 (n = 69) 较大的左眼晶状体有黄色色素沉着，这可能用于打破猎物的反光伪装。最后，我们使用视觉模型表明，增加眼睛尺寸所提供的视觉回报对于向上的眼睛比向下的眼睛要高得多，这可以解释这种独特的视觉策略的发展。本文是“昏暗光线下的视觉”主题问题的一部分。
The light environment of the mesopelagic realm of the ocean changes with both depth and viewer orientation, and this has probably driven the high diversity of visual adaptations found among its inhabitants. The mesopelagic ‘cockeyed’ squids of family Histioteuthidae have unusual eyes, as the left and right eyes are dimorphic in size, shape and sometimes lens pigmentation. This dimorphism may be an adaptation to the two different sources of light in the mesopelagic realm, with the large eye oriented upward to view objects silhouetted against the dim, downwelling sunlight and the small eye oriented slightly downward to view bioluminescent point sources. We used in situ video footage from remotely operated vehicles in the Monterey Submarine Canyon to observe the orientation behaviour of 152 Histioteuthis heteropsis and nine Stigmatoteuthis dofleini. We found evidence for upward orientation in the large eye and slightly downward orientation in the small eye, which was facilitated by a tail-up oblique body orientation. We also found that 65% of adult H. heteropsis (n = 69) had yellow pigmentation in the lens of the larger left eye, which may be used to break the counterillumination camouflage of their prey. Finally, we used visual modelling to show that the visual returns provided by increasing eye size are much higher for an upward-oriented eye than for a downward-oriented eye, which may explain the development of this unique visual strategy. This article is part of the themed issue ‘Vision in dim light’.