Animals in the News

by Gretchen Cuda Kroen

sn-dungbeetles.jpgStarry night. Using starlight, dung beetles travel relatively straight (lines inside top circle). But when the night sky is hidden, the beetles had much more difficulty keeping a straight path to the periphery (bottom circle).

Credit: (left) Emily Baird; (right) Adapted From M. Dacke et al., Current Biology, 23 (2013)
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A day in the life of a male dung beetle goes something like this: Fly to a heap of dung, sculpt a clump of it into a large ball, then roll the ball away from the pile as fast as possible. However, it turns out that the beetles, who work at night, need some sort of compass to prevent them from rolling around in circles. New research in Current Biologysuggests that the insects use starlight to guide their way. Birds, seals, and humans also use starlight to navigate, but this is the first time it’s been shown in an insect.

The whole point of rolling dung is to impress the female beetle with provisions—i.e., excrement—for her future progeny and entice her to mate. She then lays an egg in the ball and buries it in a network of tunnels more than a meter deep, where it serves as food for the developing larvae inside.

But rolling dung balls in a straight line is also key to the male dung beetle’s reproductive success. Rival males have been known to overtake a slower moving insect and claim the hard-earned treasure as their own. Competition is fiercest near the dung heap, so making a quick and efficient getaway is crucial for mating success.

The discovery that dung beetles use starlight “was an accident more than anything,” explains study author Eric Warrant, professor of zoology at the Lund University in Sweden. His research group was studying how the beetles used the polarized light patterns of the moon to stay on their paths, when one moonless night they made a surprising observation—the beetles maintained straight trajectories. “Even without the moon—just with the stars—they were still able to navigate,” Warrant says. “We were just flabbergasted.”

Read more at: ScienceMag.org

From BBC News:

The distress call of a young dolphin has been used to lure a large pod of the animals to safety, after it appeared they would strand themselves in shallow water.

Environment officials in Western Australia caught the juvenile and took it to deeper water, where its distress calls enticed the rest to follow.

One dolphin died in the incident.

A spotter plane reported that the rest – thought to number about 150 – had swum to the safety of the open sea.

The dolphins had been milling in shallow water at Whalers Cove near the town of Albany, on the south coast of the state.

“The juvenile was sending out distress signals, which was calling the dolphins in,” conservationist Deon Utber told AFP news agency.

“As soon as it was translocated to deeper waters the pod followed it out and last we saw they were swimming out to sea.”

Pod of dolphins off south coast of Western Australia - 2 February


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