Helmut Schmitz

Learn More
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(More)
The mechanical properties of the sternal cuticle of the locust were investigated by nanoindentation. Modulus and hardness of the exo-, meso-, and endocuticular layers were locally measured under dry and fully wetted conditions in the normal (i.e. perpendicular to the outer surface) as well as in the transverse direction (i.e. parallel to the alignment of(More)
Two pairs of infrared (IR) organs are situated ventrolaterally on the second and third abdominal sternites of the Australian fire beetle Merimna atrata (Buprestidae). In ventral view, each IR organ has a round IR absorbing area under which a sensory complex is attached to the epidermis. The main component of the complex is a single large multipolar neuron(More)
Nature has developed a stunning diversity of sensory systems. Humans and many animals mainly rely on visual information. In addition, they may use acoustic, olfactory, and tactile cues for object detection and spatial orientation. Beyond these sensory systems a large variety of highly specialized sensors have evolved. For instance, some buprestid beetles(More)
 The Australian buprestid beetle Merimna atrata (Coleoptera: Buprestidae) approaches forest fires because its larvae develop in freshly burnt wood. So far nothing is known about possible sensory systems enabling the beetles to detect fires and to cope with the thermal environment close to the flames. We found that M. atrata has two pairs of infrared (IR)(More)
Beetles of the genus Melanophila are able to detect infrared radiation by using specialized sensilla in their metathoracic pit organs. We describe the afferent projections of the infrared-sensitive neurons in the central nervous system. The axons primarily terminate in the central neuropil of the fused second thoracic ganglia where they establish putative(More)
Jewel beetles of the genus Melanophila and some pyrophilous species of the flat bugs genus Aradus show a pyrophilous behaviour and have developed so-called photomechanical infrared (IR) receptors. In a spherical photomechanical IR sensillum incoming IR radiation is converted into micromechanical action, finally stimulating the dendritic tip of a(More)
Globally the flat bug genus Aradus comprises about 200 species. About half a dozen Aradus species can be primarily found on burnt areas and, therefore, have been called pyrophilous. Bugs and their offspring feed on fungi growing on burnt wood. Recently, prothoracic infrared (IR) receptors have been described in the pyrophilous Australian species Aradus(More)
The Australian beetle Acanthocnemus nigricans is attracted by forest fires and has a pair of complex infrared (IR) receptor organs on the first thoracic segment. Each organ consists of a tiny sensory disc (diameter 120–130 µm) which serves as an absorbing structure for IR radiation. The disc is arranged above an air-filled cavity which is located just(More)
The pit organs of the beetle Melanophilaacuminata were stimulated with monochromatic infrared radiation using a continuous wave CO overtone infrared laser. Best sensitivity was in the wavelength range 2.8–3.5 μm. In this range a stimulus intensity of 14.7 mW cm−2 was sufficient to generate single action potentials. At a wavelength of 5 μm receptor(More)