Department of Biology, Kutztown University of Pennsylvania, Kutztown, PA 19530, USA.
J Exp Biol. 2013 Jun 1;216(Pt 11):2129-39. doi: 10.1242/jeb.084160. Epub 2013 Feb 21.
Honeybees have at least three compass mechanisms: a magnetic compass; a celestial or sun compass, based on the daily rotation of the sun and sun-linked skylight patterns; and a backup celestial compass based on a memory of the sun's movements over time in relation to the landscape. The interactions of these compass systems have yet to be fully elucidated, but the celestial compass is primary in most contexts, the magnetic compass is a backup in certain contexts, and the bees' memory of the sun's course in relation to the landscape is a backup system for cloudy days. Here we ask whether bees have any further compass systems, for example a memory of the sun's movements over time in relation to the magnetic field. To test this, we challenged bees to locate the sun when their known celestial compass systems were unavailable, that is, under overcast skies in unfamiliar landscapes. We measured the bees' knowledge of the sun's location by observing their waggle dances, by which foragers indicate the directions toward food sources in relation to the sun's compass bearing. We found that bees have no celestial compass systems beyond those already known: under overcast skies in unfamiliar landscapes, bees attempt to use their landscape-based backup system to locate the sun, matching the landscapes or skylines at the test sites with those at their natal sites as best they can, even if the matches are poor and yield weak or inconsistent orientation.
一种是磁罗盘；一种是基于太阳每日旋转和与阳光有关的天窗模式的天体或太阳罗盘；还有一种基于太阳相对于景观的运动随时间变化的记忆的备用天体罗盘。这些罗盘系统的相互作用尚未完全阐明，但在大多数情况下，天体罗盘是主要的，磁罗盘在某些情况下是备用的，而蜜蜂对太阳相对于景观的运动的记忆则是阴天的备用系统。在这里，我们想知道蜜蜂是否有任何其他的罗盘系统，例如对太阳随时间相对于磁场运动的记忆。为了检验这一点，我们在蜜蜂已知的天体罗盘系统不可用时，即在阴天和不熟悉的环境中，挑战它们定位太阳的能力。我们通过观察蜜蜂的摇摆舞来测量它们对太阳位置的了解程度，觅食者通过摇摆舞来指示相对于太阳罗盘方位的食物源方向。我们发现，蜜蜂没有超出已知的天体罗盘系统：在阴天和不熟悉的环境中，蜜蜂试图利用它们基于景观的备用系统来定位太阳，尽可能地将测试地点的景观或天际线与它们的出生地相匹配，即使匹配不佳，也会导致微弱或不一致的方向感。
