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Last Updated: Wednesday January 21 2009 15:06 GMT

Dung beetle bites back at insects

A still from one of the beetle attacks and a millipede coiled up in defence against the beetles (Photo by Trond Larsen)

It might be near the bottom of the food chain, but that hasn't stopped one tiny beetle species attacking insects that are 10 times bigger than they are.

Instead of tucking into poo, the feisty scarab dung beetles have been filmed in Peru attacking and eating millipedes.

It seems the Deltochilum valgum species now prefers biting the heads off live insects and munching away at their insides, which has surprised experts.

They say it's a really rare example of a scavenger turning into a meat-eater.

Dung beetles aren't known for being predators as they usually feast on fresh animal poo, which they gather into balls and roll with their back legs.

A dung beetle
When the Deltochilum valgum species was seen battling the millipedes, Dr Trond Larsen from America's Princeton University decided to find out if it could actually be preying on the creatures.

His team of experts set up more than 1,000 traps in Peru with different treats to tempt the beetles, including dung, fungus and fruit, as well as millipedes, which were live, injured or dead.

And they found the species only ate the millipedes, preferring the ones which were still alive but injured.

Writing about his findings in the Biology Letters journal, Dr Larsen said: "This is a remarkable transition.

"Despite its close relationships with dung feeding species, D. valgum has entirely abandoned its ball-rolling behaviour."