Humans have long used the stars to help find their way, and so have migrating birds – but dung beetles? Apparently so, according to new research.
Researchers from Sweden and South Africa have found that an African dung beetle uses the Milky Way to help it move in a straight line as it rolls a ball of dung. Their findings are reported in the January 23 issue of Current Biology.
Earlier research showed that the beetles also make use of sunlight and moonlight for the same purpose.
“This is the first time we have shown that insects use stars to guide them for orientation,” said neuroethologist Marie Dacke of Lund University in Sweden, according to an article in Science News. She added that it was also the first time they had proven that the insect uses the band of stars that makes up the Milky Way galaxy and not individual constellations or stars for guidance.
Dung beetles use animal waste for food for themselves and their larva. Competition is fierce as beetles converge on a pile of waste. The species of African beetle used in the study roll the dung into a ball – sometimes weighing up to 10 times their body weight – and roll it away from the other beetles. The beetles need to move in a reasonably straight line in order to avoid circling back where other beetles might try to take their dung ball away from them.
On earlier studies, the researchers had observed that the beetles moved much more erratically on cloudy, moonless nights, but on moonless clear nights they were still able to keep a straight course.
“Even on clear, moonless night,” Dacke explained, in a press release on the Lund University news page. “Many dung beetles still manage to orientate themselves along straight paths.”
The experiments were carried out at the Wits Planetarium in Johannesburg, South Africa, where the presence of stars and moon could be manipulated and the effects on the beetles could be observed.