Department of Biology, Lund University, Sölvegatan 35, 22362, Lund, Sweden.
Sci Rep. 2021 Oct 28;11(1):21267. doi: 10.1038/s41598-021-00407-2.
Recent interest in applying novel imaging techniques to infer optical resolution in compound eyes underscores the difficulty of obtaining direct measures of acuity. A widely used technique exploits the principal pseudopupil, a dark spot on the eye surface representing the ommatidial gaze direction and the number of detector units (ommatidia) viewing that gaze direction. However, dark-pigmented eyes, like those of honeybees, lack a visible pseudopupil. Attempts over almost a century to estimate optical acuity in this species are still debated. Here, we developed a method to visualize a stable, reliable pseudopupil by staining the photoreceptors with fluorescent dyes. We validated this method in several species and found it to outperform the dark pseudopupil for this purpose, even in pale eyes, allowing more precise location of the gaze centre. We then applied this method to estimate the sampling resolution in the frontal part of the eye of the honeybee forager. We found a broad frontal acute zone with interommatidial angles below 2° and a minimum interommatidial angle of 1.3°, a broader, sharper frontal acute zone than previously reported. Our study provides a new method to directly measure the sampling resolution in most compound eyes of living animals.
最近，人们对应用新型成像技术来推断复眼的光学分辨率产生了兴趣，这凸显了获得直接敏锐度测量的困难。一种广泛使用的技术利用主伪瞳孔，这是眼睛表面上的一个暗点，表示小眼的注视方向和观看该注视方向的探测器单元（小眼）的数量。然而，像蜜蜂那样的深色素眼睛缺乏可见的伪瞳孔。在过去的一个世纪里，人们尝试了几乎一个世纪来估计这种物种的光学敏锐度，但仍存在争议。在这里，我们开发了一种通过用荧光染料染色来可视化稳定、可靠的伪瞳孔的方法。我们在几个物种中验证了这种方法，发现它在这个目的上优于暗伪瞳孔，即使在浅色眼睛中，也能更精确地定位注视中心。然后，我们将这种方法应用于估计蜜蜂觅食者眼睛前部的采样分辨率。我们发现一个宽阔的前急性区，小眼间角度低于 2°，最小小眼间角度为 1.3°，这是一个比以前报道的更宽、更锐利的前急性区。我们的研究为直接测量大多数活体动物的复眼采样分辨率提供了一种新方法。
