Mother Nature frequently finds ways in which to astound me. This report from New Scientist has done it again.
Once a [dung] beetle (Scarabaeus satyrus) has constructed its dung ball, it moves off in a straight line in order to escape from rival beetles as quickly as possible, lest they try and steal its carefully crafted ball. This behaviour doesn't sound complicated, but several years ago, Marie Dacke of Lund University in Sweden and colleagues showed that polarised light from the moon is important for dung beetles to keep to a straight line.
Then the researchers were surprised to find the insects were able to stay on course even on a moonless night. "We thought there was something wrong in our set-up," Dacke says.
. . .
To test this, the team moved the experiment to a planetarium. By switching stars on and off, Dacke discovered that the glowing strip of the whole Milky Way was what guided the beetles' movement. "Before it was assumed insects could not use the stars because their eyes don't have the resolution to see them," she says. Navigating using the whole of the Milky Way does away with the need to see individual stars.
Dacke says the results suggest moths, locusts and other insects might navigate by the Milky Way, too.
There's more at the link.
So they're figuring out where to take a ball of dung, using the light of the stars. Is this a case of going from the ridiculous to the sublime?
Peter
I've long suspected that all migratory and night animals - birds, fish, whales, cephalopods, etcetc - use the Milky Way as their guiding light. Polaris and the Southern Cross only have a special meaning for humans. Animals just need something that doesn't move and is always aimed in the same direction. They can figure out the rest.
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