一只大黄蜂(Bombusterrestrisdalmatinus)究竟如何在像泡沫般盛开着花朵的樱桃树间快速移动,并设法从一朵花前嗖地飞到另一朵花前。根据在3月17日出版的《神经科学杂志》上报道的一项最新研究成果,大黄蜂的视觉速度是人类的5倍,这也就意味着这种昆虫的色彩视觉是所有动物中最快速的。
研究人员报告说,生物的视觉速度取决于它们眼中的感光细胞捕获周围世界快照的速度到底有多快,以及将这些快照传送回大脑所需的时间。根据在经冷冻而麻痹的大黄蜂的视网膜细胞中植入电极所记录的数据,研究人员发现,蜜蜂完成这一系列过程所需的时间比其他任何动物都要短。蜜蜂的快速视觉能力使得它们可以在斑驳的光线下迅速移动,从而能够识别出不同的形状——例如蜂巢的入口,特别是能够发现那些富含花蜜的色彩鲜艳的花朵。
原文出处:
The Journal of Neuroscience doi:10.1523/JNEUROSCI.5700-09.2010.
Differences in Photoreceptor Processing Speed for Chromatic and Achromatic Vision in the Bumblebee, Bombus terrestris
Peter Skorupski and Lars Chittka
Queen Mary University of London, Research Centre for Psychology, School of Biological and Chemical Sciences, Mile End Road, London E1 4NS, United Kingdom
Fast detection of visual change can be mediated by visual processes that ignore chromatic aspects of the visual signal, relying on inputs from a single photoreceptor class (or pooled input from similar classes). There is an established link between photoreceptor processing speed (in achromatic vision) and visual ecology. Highly maneuverable flies, for example, have the fastest know photoreceptors, relying on metabolically expensive membrane conductances to boost performance. Less active species forgo this investment and their photoreceptors are correspondingly slower. However, within a species, additional classes of photoreceptors are required to extract chromatic information, and the question therefore arises as to whether there might be within-species differences in processing speed between photoreceptors involved in chromatic processing compared with those feeding into fast achromatic visual systems. We used intracellular recording to compare light-adapted impulse responses in three spectral classes of photoreceptor in the bumblebee. Green-sensitive photoreceptors, which are known to provide achromatic contrast for motion detection, generated the fastest impulse responses (half-width, t = 7.9 ± 1.1 ms). Blue- and UV-sensitive photoreceptors (which are involved in color vision) were significantly slower (9.8 ± 1.2 and 12.3 ± 1.8 ms, respectively). The faster responses of green photoreceptors are in keeping with their role in fast achromatic vision. However, blue and UV photoreceptors are still relatively fast in comparison with many other insect species, as well as vertebrate cones, suggesting a significant investment in photoreceptor processing for color vision in bees. We discuss this finding in relation to bees' requirement for accurate learning of flower color, especially in conditions of variable luminance contrast.