Journal of Comparative Physiology A

, Volume 182, Issue 5, pp 647–657

The photomechanic infrared receptor for the detection of forest fires in the beetle Melanophila acuminata (Coleoptera: Buprestidae)

  • H. Schmitz
  • H. Bleckmann

DOI: 10.1007/s003590050210

Cite this article as:
Schmitz, H. & Bleckmann, H. J Comp Physiol A (1998) 182: 647. doi:10.1007/s003590050210


We recorded from single units of individual sensilla of the thoracic infrared (IR) pit organs of Melanophila acuminata. When the organ was stimulated with a thermal radiator whose emission spectrum was similar to that of a typical forest fire, units responded phasically with up to seven spikes within 30–40 ms at a radiation power of 24 mW cm−2. In the experiments all wavelengths shorter than 1.6 μm were excluded by a longpass IR filter. Response latencies were about 4 ms and initial impulse frequencies were up to 250 impulses per second (ips). A single spike could be generated even when stimulus duration was only 2 ms. Reduction of total radiation power from 24 mW cm−2 to 5 mW cm−2 resulted in increased response latencies of 5–6 ms and the occurrence of only two to three spikes. Initial impulse frequencies decreased to 125 ips. According to our physiological results and calculations, Melanophila should be able to detect a 10-hectare fire from a distance of 12 km. Mechanical stimuli also evoked responses of the IR sensilla. All present morphological and physiological findings lead to the conclusion that the IR receptors of Melanophila must function by means of a hitherto undescribed photomechanic mechanism.

Key words Infrared receptor Mechanoreceptor Fire ecology Insect cuticle Photoacoustics Remote sensing 

Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • H. Schmitz
    • 1
  • H. Bleckmann
    • 1
  1. 1.Institut für Zoologic der Rheinischen Friedrich-Wilhelms-Universität Bonn, Poppelsdorfer Schloß, D-53115 Bonn, Germany Tel.: +49-228 735461; Fax: +49-228 7354580 e-mail: hschmitz.zoology@t-online.deDE

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