Visual Orientation in Honey Bees

许多动物，从昆虫到人类，都能知道环境中几个重要地点的位置，比如觅食地、水坑、巢穴、庇护所或交配地。例如，像许多其他昆虫一样，觅食的蜜蜂可能会从它们的巢穴出发，飞到10公里外熟悉的花丛中的任何一个。在这样的距离上，蜜蜂无法看到花朵和周围的地标，但蜜蜂可以利用它在起点和沿途看到的熟悉的地标找到路。我们对蜜蜂如何在这种尺度上学习地标知之甚少。同样值得注意的是，在返回家园时，蜜蜂可以用著名的“舞蹈语言”来传达食物的位置，这是一系列被筑巢同伴观察到的精确的身体动作。舞蹈语言本身依赖于蜜蜂对风景的学习能力。舞者表示其飞行路径相对于太阳罗盘方向的角度；在阴天，蜜蜂可以根据以前在晴天储存的记忆来确定看不见的太阳的方向，这些记忆相对于熟悉的地标的位置。蜜蜂最初是如何形成这种记忆的，以及当它们遇到新的地标或太阳季节性地改变其运动模式时，它们是如何更新这种记忆的，这仍然是一个谜。为了研究蜜蜂如何利用储存在记忆中的视觉信息来完成这些定向壮举，戴尔博士将观察有经验的蜜蜂在视觉线索以特定方式改变时的反应。这样的实验可以揭示环境中的哪些特征（例如，地标的大小、形状、距离和颜色，或者太阳的位置和运动速度）为蜜蜂提供了空间信息，特征之间的关系是如何被记住的，记忆是如何随着时间的推移而发展的，以及当蜜蜂遇到新信息时，以前储存的信息会发生什么。因此，我们的目标是揭示利用视觉空间信息进行定向的一般处理策略。蜜蜂在熟悉环境中的视觉方向是由一个比针尖大一点的大脑控制的。脊椎动物，尤其是人类更大的大脑，显然能够处理相当复杂的事情。然而，复杂性的不同并不一定意味着在基本的神经过程中存在巨大的差异。事实上，生物学中一个反复出现的主题是，通过研究简单的有机体，有时更容易阐明一般原理。因此，除了阐明蜜蜂如何了解环境之外，这些研究还可以帮助认知科学家完善他们关于更复杂生物体（包括人类）空间定向机制的假设。

Many animals, from insects to human beings, can learn the locations of several important sites in the environment, such as feeding places, watering holes, nests, shelters, or mating grounds. For example, foraging honey bees, like many other insects, may range widely from their nest, traveling to any of several familiar flower patches as far away as 10 kilometers. Over such a distance, the flowers and the landmarks around them cannot be seen by a bee setting out, yet the bee can find its way using familiar landmarks it sees at the starting point and along the way. Little is known about how bees learn landmarks on this scale. Equally remarkable, on returning home the bee can communicate the location of the food using the famous "dance language," a series of precise body movements observed by nestmates. The dance language itself relies on the bee's ability to learn about the landscape. A dancer indicates the angle of its flight path relative to the sun's compass direction; on cloudy days the bee can determine the direction of the unseen sun by referring to a memory, stored previously in sunny weather, of its position relative to familiar landmarks. It is still a riddle how bees form this memory in the first place, and how they update it as they encounter new landmarks or as the sun changes its pattern of movement seasonally. To study how bees use visual information stored in memory to perform these feats of orientation, Dr. Dyer will observe the responses of experienced bees when visual cues are altered in specific ways. Such experiments can reveal which of many features of the environment (e.g., the size, shape, distance, and color of landmarks, or the sun's position and rate of movement) provide spatial information to bees, how the relationships among features are remembered, how memories develop over time, and what happens to previously stored information when a bee encounters new information. Thus, the goal is to uncover general processing strategies underlying the use of visual spatial information for orientation. The visual orientation of a bee in a familiar environment is controlled by a brain little larger than the head of a pin. The larger brains of vertebrates, and especially of human beings, are obviously capable of processing that is considerably more complex. However, a difference in complexity does not necessarily imply that there is a dramatic difference in the basic neural processes. A recurrent theme in biology, in fact, is that general principles can sometimes be more easily elucidated by studying simple organisms. Hence, in addition to throwing light on how bees learn about their environment, these studies may help cognitive scientists refine their hypotheses regarding the mechanisms of spatial orientation in more complex organisms, including man.