Dung beetles record a mental image of the positions of the Sun, the Moon and the stars and use the snapshot to navigate, according to researchers.
Scientists in Sweden found that the beetles capture the picture of the sky while dancing on a ball of manure.
As they roll away with their malodorous prize, the beetles compare the stored image with their current location.
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A Snapshot-Based Mechanism for Celestial Orientation
Current Biology
Basil el Jundi, James J. Foster, Lana Khaldy, Marcus J. Byrne, Marie Dacke, Emily Baird
publication stage:
In Press Corrected Proof
Summary
In order
to protect their food from competitors, ball-rolling dung beetles detach
a piece of dung from a pile, shape it into a ball, and roll it away
along a straight path [ 1 ]. They appear to rely exclusively on
celestial compass cues to maintain their bearing [ 2–8 ], but the
mechanism that enables them to use these cues for orientation remains
unknown. Here, we describe the orientation strategy that allows dung
beetles to use celestial cues in a dynamic fashion. We tested the
underlying orientation mechanism by presenting beetles with a
combination of simulated celestial cues (sun, polarized light, and
spectral cues). We show that these animals do not rely on an innate
prediction of the natural geographical relationship between celestial
cues, as other navigating insects seem to [ 9, 10 ]. Instead, they
appear to form an internal representation of the prevailing celestial
scene, a “celestial snapshot,” even if that scene represents a physical
impossibility for the real sky. We also find that the beetles are able
to maintain their bearing with respect to the presented cues only if the
cues are visible when the snapshot is taken. This happens during the
“dance,” a behavior in which the beetle climbs on top of its ball and
rotates about its vertical axis [ 11 ]. This strategy for reading
celestial signals is a simple but efficient mechanism for straight-line
orientation.
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