Horsefly object-directed polarotaxis is mediated by a stochastically distributed ommatidial subtype in the ventral retina
Horsefly object-directed polarotaxis is mediated by a stochastically distributed ommatidial subtype in the ventral retina
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DOI：
10.1073/pnas.1910807116
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发表时间：
2019-10-22
影响因子：
11.1
通讯作者：
Belusic, Gregor
中科院分区：
文献类型：
--
作者：
Meglic, Andrej;Ilic, Marko;Belusic, Gregor
许多昆虫的腹侧复眼含有偏振敏感的光感受器，但很少有人知道它们是如何整合到视觉功能中的。在雌性马蝇中，动物皮毛的偏振反射是宿主检测的关键刺激。为了了解偏振视觉是如何介导的腹侧复眼，我们调查了带眼的棕色虻虻bromius使用解剖，生理和行为的方法。视网膜的连续电子显微镜切片和单细胞记录被用来确定光感受器的光谱和偏振灵敏度（PS）。小眼有2个随机分布的亚型，与其它蝇类的淡黄色相似。重要的是，浅色类似物包含具有高PS的正交分析受体对，其由紫外（UV）敏感的R7和UV和蓝色敏感的R8形成，而黄色类似物中的UV敏感的R7和绿色敏感的R8总是具有低PS。我们测试了马蝇在该领域的趋极性，使用诱饵与控制光谱和偏振组合物。没有UV和蓝色成分的偏振反射使诱饵失去吸引力，而没有绿色成分的反射增加了它们的吸引力。这是一致的趋极化性被引导的差分信号从偏振分析仪在苍白的类似物，并与黄色类似物的抑制作用。我们的研究结果揭示了随机分布的感觉单位与特定的劳动分工作为独立的和相反的输入通道的视觉指导。
The ventral compound eye of many insects contains polarization-sensitive photoreceptors, but little is known about how they are integrated into visual functions. In female horseflies, polarized reflections from animal fur are a key stimulus for host detection. To understand how polarization vision is mediated by the ventral compound eye, we investigated the band-eyed brown horsefly Tabanus bromius using anatomical, physiological, and behavioral approaches. Serial electron microscopic sectioning of the retina and single-cell recordings were used to determine the spectral and polarization sensitivity (PS) of photoreceptors. We found 2 stochastically distributed subtypes of ommatidia, analogous to pale and yellow of other flies. Importantly, the pale analog contains an orthogonal analyzer receptor pair with high PS, formed by an ultraviolet (UV)-sensitive R7 and a UV- and blue-sensitive R8, while the UV-sensitive R7 and green-sensitive R8 in the yellow analog always have low PS. We tested horsefly polarotaxis in the field, using lures with controlled spectral and polarization composition. Polarized reflections without UV and blue components rendered the lures unattractive, while reflections without the green component increased their attractiveness. This is consistent with polarotaxis being guided by a differential signal from polarization analyzers in the pale analogs, and with an inhibitory role of the yellow analogs. Our results reveal how stochastically distributed sensory units with modality-specific division of labor serve as separate and opposing input channels for visual guidance.