for National Geographic News
This is the last in this week's series of articles on how military and other scientists are turning to nature to find the next generation of powerful secret weapons. Please look under the picture caption for links to the earlier articles. The stories all air on National Geographic EXPLORER at 8 p.m. ET/PT this Sunday on MSNBC.
Some like it hot. Some beetles like it smoking hot.
When a forest goes up in flames normally elusive Melanophila acuminata beetles from miles around head for the inferno in droves, joining a mating frenzy so that the females can lay their eggs in the freshly burned trees.
The beetles are attracted to the smoldering wood because the burned trees no longer have active defense mechanisms such as flowing sap. Larvae feed on the layer of plant tissue that lies between the bark and wood, and as the beetles grow they chew into the wood itself.
"They are adapted to an ecological niche to use fire-burned trees as a food source," said Helmut Schmitz, a zoologist at the University of Bonn in Germany and leading researcher on the beetle's ability to detect fires.
Of great interest to Schmitz, his colleagues, and the U.S. military are the sensors on the beetles' chests that allow them to determine when and where a fire is burning so that they can race towards the flames and get first dibs on the smoldering trees.
The researchers want to mimic the beetles' sensors, which are finely tuned to detect infrared radiation in the spectrum put off by forest fires. Robotic devices built with this technology could detect chemical or infrared emissions more cost-efficiently than current technology.
For example, the U.S. Department of Defense has a variety of systems that use infrared sensors, such as heat-seeking missiles, but in order for the sensors to work they must be cooled to freezing temperatures, which is expensive.
"If you get rid of the need for cooling but maintain sensitivity you have a tremendous gain in weight, size, complexity, maintenance, durability, et cetera," said Hugh DeLong, a contract officer with the U.S. Air Force's Air Force office of Scientific Research in Arlington, Virginia.
The Air Force is funding a portion of the research by Schmitz and his colleagues in the hopes that the scientists can mimic the beetle's sensor system to design a sensor for the military.
Natural Sensor
Melanophila acuminata beetles have what scientists call pit organs in their chests right at the point where the legs are attached to the body. Within each pit are 60 to 70 sensors called sensilla in insects. Each sensillum consists of a little sphere which is made of the same hard skin material that covers the beetle's outer shell. Each sphere is connected by nerves to a highly-sensitive mechanoreceptive sensory cell.
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