PDF(Pubmed)
Abstract：
BACKGROUND: Insects have evolved complex visual systems and display an astonishing range of adaptations for diverse ecological niches. Species of Drosophila melanogaster subgroup exhibit extensive intra- and interspecific differences in compound eye size. These differences provide an excellent opportunity to better understand variation in insect eye structure and the impact on vision. Here we further explored the difference in eye size between D. mauritiana and its sibling species D. simulans.
RESULTS: We confirmed that D. mauritiana have rapidly evolved larger eyes as a result of more and wider ommatidia than D. simulans since they recently diverged approximately 240,000 years ago. The functional impact of eye size, and specifically ommatidia size, is often only estimated based on the rigid surface morphology of the compound eye. Therefore, we used 3D synchrotron radiation tomography to measure optical parameters in 3D, predict optical capacity, and compare the modelled vision to in vivo optomotor responses. Our optical models predicted higher contrast sensitivity for D. mauritiana, which we verified by presenting sinusoidal gratings to tethered flies in a flight arena. Similarly, we confirmed the higher spatial acuity predicted for Drosophila simulans with smaller ommatidia and found evidence for higher temporal resolution.
CONCLUSIONS: Our study demonstrates that even subtle differences in ommatidia size between closely related Drosophila species can impact the vision of these insects. Therefore, further comparative studies of intra- and interspecific variation in eye morphology and the consequences for vision among other Drosophila species, other dipterans and other insects are needed to better understand compound eye structure-function and how the diversification of eye size, shape, and function has helped insects to adapt to the vast range of ecological niches.
RESULTS: We confirmed that D. mauritiana have rapidly evolved larger eyes as a result of more and wider ommatidia than D. simulans since they recently diverged approximately 240,000 years ago. The functional impact of eye size, and specifically ommatidia size, is often only estimated based on the rigid surface morphology of the compound eye. Therefore, we used 3D synchrotron radiation tomography to measure optical parameters in 3D, predict optical capacity, and compare the modelled vision to in vivo optomotor responses. Our optical models predicted higher contrast sensitivity for D. mauritiana, which we verified by presenting sinusoidal gratings to tethered flies in a flight arena. Similarly, we confirmed the higher spatial acuity predicted for Drosophila simulans with smaller ommatidia and found evidence for higher temporal resolution.
CONCLUSIONS: Our study demonstrates that even subtle differences in ommatidia size between closely related Drosophila species can impact the vision of these insects. Therefore, further comparative studies of intra- and interspecific variation in eye morphology and the consequences for vision among other Drosophila species, other dipterans and other insects are needed to better understand compound eye structure-function and how the diversification of eye size, shape, and function has helped insects to adapt to the vast range of ecological niches.
摘要：
背景：昆虫已经进化出复杂的视觉系统，并对不同的生态位表现出惊人的适应范围。果蝇亚组的物种在复眼大小上表现出广泛的种内和种间差异。这些差异为更好地了解昆虫眼睛结构的变化和对视觉的影响提供了极好的机会。在这里，我们进一步探索了D.mauritana和它的兄弟物种D.simulans之间的眼睛大小差异。
结果：我们证实，与D.simulans相比，D.maurituana的眼睛比D.simulans的眼睛更多，更宽，因为它们最近在大约240,000年前分开了。眼睛大小的功能影响，特别是ommatidia的大小，通常仅基于复眼的刚性表面形态来估计。因此,我们使用3D同步加速器辐射层析成像来测量3D光学参数，预测光学容量，并将模拟的视力与体内视运动反应进行比较。我们的光学模型预测D.mauritana的对比敏感度更高，我们通过在飞行舞台上为系绳的苍蝇提供正弦光栅来验证。同样，我们证实了更高的空间敏锐度预测果蝇模拟与较小的眼虫，并发现了更高的时间分辨率的证据。
结论：我们的研究表明，即使是紧密相关的果蝇物种之间的眼虫大小的细微差异也会影响这些昆虫的视力。因此,进一步比较研究眼睛形态的种内和种间变化以及其他果蝇物种对视力的影响，需要其他双翅目和其他昆虫来更好地了解复眼结构-功能以及眼睛大小的多样化，形状,和功能帮助昆虫适应广泛的生态位。
结果：我们证实，与D.simulans相比，D.maurituana的眼睛比D.simulans的眼睛更多，更宽，因为它们最近在大约240,000年前分开了。眼睛大小的功能影响，特别是ommatidia的大小，通常仅基于复眼的刚性表面形态来估计。因此,我们使用3D同步加速器辐射层析成像来测量3D光学参数，预测光学容量，并将模拟的视力与体内视运动反应进行比较。我们的光学模型预测D.mauritana的对比敏感度更高，我们通过在飞行舞台上为系绳的苍蝇提供正弦光栅来验证。同样，我们证实了更高的空间敏锐度预测果蝇模拟与较小的眼虫，并发现了更高的时间分辨率的证据。
结论：我们的研究表明，即使是紧密相关的果蝇物种之间的眼虫大小的细微差异也会影响这些昆虫的视力。因此,进一步比较研究眼睛形态的种内和种间变化以及其他果蝇物种对视力的影响，需要其他双翅目和其他昆虫来更好地了解复眼结构-功能以及眼睛大小的多样化，形状,和功能帮助昆虫适应广泛的生态位。
