Criminal cases can often only be solved using forensics to piece together physical evidence and reconstruct what happened. Prof. Dr. Helmut Schmitz from the Institute of Zoology at the University of Bonn and Dr. Herbert Bousack from the Peter Grnberg Institut at the Forschungzentrum Jlich went through the same experience. Prof. Schmitz has been researching fire beetles of the genus Melanophila and their sophisticated IR sensors, which these pyrophilous insects use to detect forest fires, for many years. This is a very special ecological niche. "It allows the beetle larvae to freely eat their way through the wood because the trees, which have been killed by great heat, can no longer fight back, and there are hardly any predators that would eat them in freshly burned forests," the Bonn zoologist reported.
A tiny sphere senses changes in pressure due to heat
Meanwhile, with the help of the Forschungszentrum caesar in Bonn and the Technische Universitt Dresden, the researchers have unraveled the functional principle of this so-called photo-mechanical beetle infrared sensor, and they have started to work on a technical reconstruction of this natural prototype. Tiny cuticula spheres of the beetles' IR receptors at 0.02 mm, smaller than the diameter of a fine hair are filled with water and absorb IR radiation very well. Due to the fact that they heat up, the water in particular expands suddenly, and the resulting change in pressure is immediately detected by highly sensitive mechano-sensitive sensory cells. "However, an important question had remained unanswered how sensitive is the sensor?" asked Prof. Schmitz. This question could be best answered by equipping Melanophila beetles with mini transmitters on their search for forest fires. "Then we would be able to log the distance flown to the burnt area and, based on this distance, calculate the minimum required heat radiation the beetles are attracted by," explained the zoolog
|Contact: Prof. Dr. Helmut Schmitz|
University of Bonn