By Louise Dalziel

Jewel beetles can "smell" the products of a fire

There is a beetle that, instead of fleeing like most other animals when confronted with fire, spreads its wings and flies in droves straight towards the inferno.

In fact, the jewel beetle, or black fire beetle as it's known in Canada, needs a blazing forest fire to breed.

Anecdotal reports suggest the beetles will travel many kilometres to reach a forest fire.

When they arrive, they are guaranteed sex and a safe place to lay their eggs with a great supply of food laid on for the next generation.

The beetles can join a mating frenzy, free from any threat of predation; everything that might fancy eating them having already fled from the blaze.

They lay their eggs in the burnt wood of dead trees. Once inside the charred tree trunks and branches, the eggs can hatch and munch on their surroundings safely cocooned inside the dead wood.

If alive, the trees would protest to beetle-nibbling by exuding toxic chemicals, drowning the beetle larvae in sticky resin or squashing them to death with prolific cell growth.

Mysterious pits

Back in 1960, a Canadian entomologist called William George Evans was sitting in a restaurant in Edmonton when a shiny black beetle landed beside his plate on the white tablecloth.

Having recently moved to Alberta, he was unfamiliar with this insect so, driven by scientific curiosity, he scooped the beetle up into the lid of his fountain pen and took it home to identify.

His reference books revealed that he had captured Melanophila acuminate.

The beetles are guaranteed sex and a safe place to lay their eggs

His identification key also referred to tiny pits on the beetle's thorax or chest.

Sure enough, when Professor Evans looked closely, there they were. He studied the beetle for a number of years until he was confident that he knew what the function of the mysterious pits was.

He believed they must be sensory pits, densely packed with tiny receptors that enabled the beetle to sense infrared radiation; the heat given off by a blazing inferno.

The problem was nobody believed that a beetle was capable of doing this and Professor Evans' observations fell, for many years, on deaf ears.

Now, a team of German researchers, led by Dr Helmut Schmitz at the University of Bonn, has not only confirmed Professor Evans' findings but it has taken the understanding of how the beetle senses its environment to a higher level.

Flickering flames

Melanophila acuminata uses a combination of supersensitive cues to seek out a fire.

They see the red flickering flames, they hear the crackling of the burning wood and, as chemical ecologist Dr Stephan Schutz discovered, they use supersensitive receptors on their antennae to "smell" the products of a fire - even in minute quantities.

It has taken years of meticulous research by a team of biologists, physiologists, chemical ecologists and finally a physicist to start to unravel the beetle's infrared detecting secrets.

They lay their eggs in the burnt wood of dead trees

Since working on M. acuminate, the German team has discovered that two other species of fire beetle, this time in Australia, also use infrared detectors to guide them to fire.

The exciting thing about this is that the infrared detectors these beetles use are different from the ones of their Northern Hemisphere cousins.

Now, the scientists are putting their knowledge of how the beetles sense infrared radiation to use.

With the help of engineers they plan to develop the next generation of infrared detectors. They already have a working prototype and are busy trying to increase its sensitivity and make it smaller.

It does not come as any surprise that the Defence Advanced Research Projects Agency (Darpa) in the US can see the massive military potential for a new generation of supersensitive, miniature, robust, uncooled, infrared detectors inspired by a humble heat-seeking beetle.