Australia's largest mimicry group uses golden sheen to deter predators

Feb. 8 (UPI) -- Scientists have identified 140 species in Australia all using the same mimicry tactic to ward off predators. It's the largest mimicry complex, or mimicry group, discovered in Australia, and one of the biggest on the planet.

All 140 of the species use a golden sheen to ward off would-be attackers. The majority of the species are ants, but the complex also includes leafhoppers, spiders, wasps and true bugs.

Mimicry only works if there is an actual threat to back it up. A golden sheen against a dark black backdrop is no threat, but predators have learned to associate the color combo with actual defense mechanisms -- like the threat of poisons or toxins.

"Many animals use bright colours to warn a potential predator that they can defend themselves, and predators often learn to heed such warnings and avoid these animals in future," Marie Herberstein, a professor of biological sciences at Macquarie University, said in a news release. "Wasps, for example, are armed with a harmful sting and advertise this fact through their distinctive yellow and black stripes. Animals that mimic another animal's warning signals can reap the benefit of being left alone by predators even if they are otherwise undefended."

Researchers analyzed the stomach contents of common Australian predators -- including spiders, birds and lizards -- to measure the efficacy of the defense strategy. The findings, detailed in the journal eLife, suggest the mimicry works.

"Most of these common predators avoided the mimics regardless of whether they were palatable or unpalatable to eat," Herberstein said. "Therefore species with this gold colour without defences such as spines and foul-tasting chemicals can benefit by deceiving predators into thinking they are unpalatable."