Monopolatic motion vision in the butterfly Papilio xuthus
Monopolatic motion vision in the butterfly Papilio xuthus
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DOI：
10.1242/jeb.191957
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发表时间：
2019-01-01
影响因子：
2.8
通讯作者：
Arikawa, Kentaro
中科院分区：
文献类型：
--
作者：
Stewart, Finlay J.;Kinoshita, Michiyo;Arikawa, Kentaro
凤蝶（Papilio xuthus）可以感知光的线性偏振。利用一种新的偏振投影系统，我们最近证明了P. xuths可以检测基于偏振对比度的视觉运动。在本研究中，我们试图通过行为实验来推断这种基于偏振的运动视觉的机制。凤蝶不能感知非偏振光和对角偏振光之间的对比，这意味着它们不能明确地估计偏振的角度和程度，至少就运动检测而言。此外，它们将亮度和偏振线索混为一谈，使得明亮的垂直偏振光类似于暗淡的非偏振光。这些观察结果与单通道“单极”检测器机制一致。我们扩展了我们现有的模型的运动视觉在P. xuthus纳入这些偏振的研究结果，并得出结论，光感受器可能形成的基础上假定的单极偏振检测器是R3和R4，最大限度地响应水平偏振绿色光。R5-R8，我们建议，形成一个偏振不敏感的二级通道调谐到更长的光波长。与此一致，我们看到更大的敏感性，偏振绿光刺激比主观等亮度的红色。有些违反直觉，我们的模型预测最大的敏感性垂直偏振光，由于感光器响应的非线性，光偏振的角度正交的单极检测器的方向提供了最大的对比度与非偏振光。
The swallowtail butterfly Papilio xuthus can perceive the linear polarization of light. Using a novel polarization projection system, we recently demonstrated that P. xuthus can detect visual motion based on polarization contrast. In the present study, we attempt to infer via behavioural experiments the mechanism underlying this polarization-based motion vision. Papilio xuthus do not perceive contrast between unpolarized and diagonally polarized light, implying that they cannot unambiguously estimate angle and degree of polarization, at least as far as motion detection is concerned. Furthermore, they conflate brightness and polarization cues, such that bright vertically polarized light resembles dim unpolarized light. These observations are consistent with a one-channel 'monopolatic' detector mechanism. We extend our existing model of motion vision in P. xuthus to incorporate these polarization findings, and conclude that the photoreceptors likely to form the basis for the putative monopolatic polarization detector are R3 and R4, which respond maximally to horizontally polarized green light. R5-R8, we propose, form a polarization-insensitive secondary channel tuned to longer wavelengths of light. Consistent with this account, we see greater sensitivity to polarization for green-light stimuli than for subjectively equiluminant red ones. Somewhat counter-intuitively, our model predicts greatest sensitivity to vertically polarized light; owing to the non-linearity of photoreceptor responses, light polarized to an angle orthogonal to a monopolatic detector's orientation offers the greatest contrast with unpolarized light.