Honeybees can learn the relationship between the solar ephemeris and a newly experienced landscape: a confirmation.

Honeybees learn the spatial relationship between the sun's pattern of movement and the landscape immediately surrounding their nest, which allows bees to locate the sun under overcast skies by reference to the landscape alone. Surprisingly, when bees have been transplanted from their natal landscape to a rotated twin landscape - such as from one treeline to a similar but differently oriented treeline - they fail to learn the relationship between the sun and the second landscape. This raises the question of whether bees can ever learn the relationship between the sun's pattern of movement and a landscape other than their natal one. Here we confirm, with new and necessary controls, that bees can indeed learn the relationship between the sun's pattern of movement and a second (that is, non-natal) landscape, if the second landscape is panoramically different from the bees' natal site. We transplanted bees from their natal site to a panoramically different second site and, 3 days later, tested the bees' knowledge of the relationship between the sun and the second landscape. The test involved observing the bees' communicative dances under overcast skies at a third site that was a rotated twin of the second. These bees oriented their dances using a memory of the sun's course in relation to the second landscape, indicating that they had learned this relationship. Meanwhile, control bees transplanted directly from the natal site to the third site, skipping the second, danced differently, confirming the importance of the experimental bees' experience at the second site.

The depth of the honeybee's backup sun-compass systems.

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.