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93. Melanophila acuminata (DeGeer, 1774) County Records (n = 75): Anoka, Beltrami, Carlton, Cass, Clearwater, Cook, Crow Wing, Hennepin, Kanabec, Kandiyohi, Koochiching, Lake, Olmsted, Otter Tail, Pine, Polk, Ramsey, Red Lake, Roseau, and St. Louis. Collection Dates: 27 May–30 September. Minnesota Hosts: Unspecified in collection records. Larval hosts recorded as Abies balsamea, Betula alleghaniensis, Picea glauca, Pinus resinosa, P. strobus, and Thuja occidentalis. Collection Method: In Lindgren funnel trap on Pinus banksiana., Published as part of Hallinen, Marie J., Steffens, Wayne P., Schultz, Jennifer L. & Aukema, Brian H., 2021, The Buprestidae (Coleoptera) of Minnesota, with a Discussion of the Emerald Ash Borer, Agrilus planipennis Fairmaire, pp. 173-190 in The Coleopterists Bulletin 75 (1) on page 185, DOI: 10.1649/0010-065X-75.1.173, http://zenodo.org/record/4837088

Objective: The aim of this study is to investigate the anatomy and histology of Melanophila picta decastigma (Fabricius) (Coleoptera: Buprestidae). Materials and Methods: Some of the samples were fixed in 10% formaldehyde for light microscopy, others were fixed with 2.5% glutaraldehyde for scanning electron microscopy (SEM). Then the samples were examined by using stereo, light, and SEM. Results: The digestive tract in M. picta decastigma consists of foregut, midgut, and hindgut. The foregut is composed of the pharynx, esophagus, crop and proventriculus. The foregut showed muscle layers followed by intima and epithelium. There is a long, tubular pair of gastric caeca in the anterior part of the midgut. In cross-sections, a single-layered cylindrical epithelium with a short striated border. The midgut showed that the epithelial lining was substantially folded, giving its lumen a curved profile. These monolayered columnar epithelial cells had their nuclei located medially, and apically they have a striated border. The midgut surface was covered by rounded structures called regenerative crypts. The main sections of hindgut (pyloric valve, ileum, colon and rectum) were clearly observed. In the hindgut sections, there appeared to be a highly folded cuticular lining, a monolayer cubic epithelium and a very muscular wall. Conclusions: Studies on the digestive tract histo-anatomy of M. picta decastigma will add more information to assist in experimental, taxonomical, histological, and anatomical studies about insect tissues and will serve as a basis for control studies.

Recently, large numbers of Melanophila unicolor Gory, 1841 were attracted to furnaces and cooling copper at a smelter at Tsumeb, Namibia, where the beetles are colloquially known as 'furnace-beetles'. The smelter is surrounded by indigenous savanna woodland. The beetles were alleged by workers to inflict a painful bite. Specimens were sent to us for identification; the results are reported in this communication.

45. Melanophila atropurpurea (Say, 1823) Parish records (n = 1): St. Tammany Parish (LSAM). Potential larval host in Louisiana: Unknown, possibly Pinus spp. Collection date: 13 August. Comments: New State Record: St. Tammany Parish, 4.2 mi N Abita Springs, 30.5162°N, 89.9547°W, collected at mercury vapor light, 13 Aug. 2007, V. Brou (n = 1)., Published as part of Carlton, Christopher E., MacRae, Ted C., Tishechkin, Alexey K., Bayless, Victoria L. & Johnson, Wood, 2018, Annotated Checklist of the Buprestidae (Coleoptera) from Louisiana, pp. 351-367 in The Coleopterists Bulletin 72 (2) on page 357, DOI: 10.1649/0010-065X-72.2.351, http://zenodo.org/record/5382706

The European fire beetle Melanophila cuspidata oviposits on stems damaged by fire to provide its xylophagous larvae with nutrition. We investigated the beetle's ability to estimate the heating stage of the wood beneath the charred bark by means of volatiles. Such biologically preselected volatiles can enable a reliable differentiation between fresh, heated, and burned wood and can be used for early fire warning systems. 25 compounds of heated pine wood chips (Pinus sylvestris) were identified and quantified by GC–MS. Electrophysiological experiments (GC–MS/EAD, EAG) and behavioral studies with M. cuspidata revealed eight electrophysiologically active and behaviorally attractive compounds. Furfural was selected as a marker volatile for heated wood and a nanoporous semiconductor metal oxide gas sensor was developed for the detection of this compound. In a burning chamber, this sensor detected furfural at low concentration prior to the ignition of pine wood chips (P. sylvestris). The furfural emission in this chamber was monitored simultaneously by an online mass-spectrometer. The utilization of M. cuspidata as an information filter for marker volatile selection and the feasibility of the nanoporous sensor for early fire warning systems in the wood processing industry are discussed.

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 mechanosensitive sensory cell. The tip is located inside a tiny cuticular sphere with a diameter of about 12 μm. The material properties of the different cuticular components of this sphere are of great importance for stimulus generation. We measured the modulus and hardness of the outer exocuticular shell of the sphere and the mesocuticle inside the core. Measurements were made by nanoindentation at sensilla which were partly cut open under dry as well as under rewetted (i.e. quasi-natural) conditions. We found that in the rewetted sensilla the outer exocuticular shell of the sphere in the Melanophila sensillum is about 50% harder and 20% stiffer than reference exocuticle, and that in both species especially the rewetted mesocuticle of the inner core of the IR sensilla is significantly softer (about 80% in Melanophila ) and more compliant (about 90% also in Melanophila ) than the reference mesocuticle. The findings can be interpreted as special adaptations of the cuticular microdomains of photomechanical infrared sensilla to enhance thermomechanical performance and, thereby, sensitivity.

Beetles of the genus Melanophila and certain flat bugs of the genus Aradus approach forest fires. For the detection of fires and of hot surfaces, the pyrophilous species of both genera have developed infrared (IR) receptors, which have developed from common hair mechanoreceptors. Thus, this type of insect IR receptor has been termed photomechanic. Compared to a hair mechanoreceptor, a photomechanic IR sensillum shows the following special features, (i) The formation of a complex cuticular sphere instead of the bristle; the sphere consists of an outer exocuticular shell as well as of a cavernous microfluidic core, (ii) The enclosure of the dendritic tip of the mechanosensitive neuron inside the core in a liquid-filled chamber. Hence, we propose that a photomechanic IR sensillum most probably acts as a microfluidic converter of IR radiation into an increase in internal pressure in- side the sphere, which is measured by a mechanosensitive neuron. A simple model for this biological IR sensor is the Golay sensor, which is filled with a liquid instead of gas. Here, the absorbed IR radiation results in a pressure increase of the liquid and the deflection of a thin membrane. For the evaluation of this model, analytical formulas are presented, which permit the calculation of the pressure increase in the cavity, the deformation of the membrane and the time constant of an artificial leak to compensate ambient temperature changes. Some organic liquids with high thermal expansion coefficients may improve the deflection of the membrane compared to water.

Melanophila drummondi ab. nicolayi Obenberger 1944 has been listed in some of the more recent literature as M. drummondi nicolayi Obenberger, thus creating problems with interpretation of its status as an unavailable name under Articles 13 and 45.6.2 of the ICZN (1999). This issue is discussed. Based on examination of a photograph of the type specimen, we consider the taxon unworthy of separation from Phaenops drummondi (Kirby 1837), which is compared to similar species occurring in its range. A new distribution record and summary of known larval hosts are provided for the species.

A number of abiotic and biotic factors indicates that poplars of the section Aigeiros cultivated in the Northern Lowlands of Iraq in irrigated plantations had to grow at or near their ecological pessimum. These conditions make them optimal hosts for their dangerous insect enemy Melanophila picta (Pall.) and other insects and pathogens, occuring on the native Populus euphratica in small numbers. Favoured by the hot climate from the point of view of this insects specific temperature requirements and by the fact that environmental factors for these poplars reach in Iraq the negative culmination and putting to degeneration that part of the tree which is needed by Melanophila picta larvae, just at that season and in that state, development and further spread is ensured also from the point of view of nutrition. This coincidence of factors which favours directly and indirectly that insect, leads consequently to outbreaks and is considered responsible for the complete destruction of the plantations, to which a number of other insects and pathogens mentioned in this paper, very probably might have contributed. Zusammenfassung Forstentomologische Studien im Irak. II. Das Schadlingsproblem beim Pappelanbau Eine Anzahl abiotischer und biotischer Faktoren weist darauf hin, das Pappeln der Sektion Aigeiros, welche im nordlichen Flachland des Irak angebaut wurden, im oder in der Nahe des Bereichs ihres okologischen Pessimums wachsen. Dieser Umstand machte sie zu optimalen Wirtspflanzen fur den gefahrlichen Pappelschadling Melanophila picta (Pall.) sowie andere Insekten und Krankheitserreger, welche an der einheimischen Populus euphratica in geringerer Zahl vorkommen. Melanophila picta wird einerseits hinsichtlich seiner spezifischen Temperaturanforderungen vom heisen Klima im Irak begunstigt, andererseits auch durch ein optimales Nahrungsangebot, da die Umweltfaktoren gerade zu dieser Jahreszeit einen Hohepunkt der Ungunst erreichen und jene Teile der Baume physiologischer Degeneration aussetzen, welche die Melanophila-Larven eben zu dieser Zeit und in diesem Zustand als Nahrung benotigen. Dieses Zusammentreffen von Faktoren, die direkt sowie indirekt den Schadling stark begunstigen, wird als Ursache fur die Massenvermehrung und die vollige Vernichtung der Pappelplantagen angesehen, zu der auch eine Reihe von anderen Insekten und Krankheitserregern, die in dieser Arbeit erwahnt sind, beigetragen haben mogen.

The thoracic infrared (IR) sensilla of the pyrophilous jewel beetle Melanophila acuminata most likely have evolved from hair mechanoreceptors (sensilla trichodea). To further elucidate the sensory transduction mechanism, the morphology of IR sensilla and of neighbouring hair mechanoreceptors was investigated by using conventional electron microscopical techniques (SEM, TEM) in combination with focused ion beam milling (FIB). It was assumed that any deviation from the bauplan of a sensillum trichodeum is of particular concern for the transduction of IR radiation into a mechanical stimulus. Thus, the structures supposed to be relevant for stimulus uptake and transduction were homologized. Compared to a hair mechanoreceptor, an IR sensillum shows the following special features: (i) the formation of a complex cuticular sphere instead of the bristle; the sphere consists of an outer exocuticular shell as well as of an inner porous mesocuticular part. (ii) The enclosure of the dendritic tip of the mechanosensitive neuron inside the sphere in a fluid-filled inner pressure chamber which is connected with a system of microcavities and nanocanals in the mesocuticular part. Hence we propose that an IR sensillum most probably acts as a microfluidic converter of infrared radiation into an increase in internal pressure inside the sphere which is measured by the mechanosensitive neuron.

Every year forest fires cause severe financial losses in many countries of the world. Additionally, lives of humans as well as of countless animals are often lost. Due to global warming, the problem of wildfires is getting out of control; hence, the burning of thousands of hectares is obviously increasing. Most important, therefore, is the early detection of an emerging fire before its intensity becomes too high. More than ever, a need for early warning systems capable of detecting small fires from distances as large as possible exists. A look to nature shows that pyrophilous “fire beetles” of the genus Melanophila can be regarded as natural airborne fire detection systems because their larvae can only develop in the wood of fire-killed trees. There is evidence that Melanophila beetles can detect large fires from distances of more than 100 km by visual and infrared cues. In a biomimetic approach, a concept has been developed to use the surveying strategy of the “fire beetles” for the reliable detection of a smoke plume of a fire from large distances by means of a basal infrared emission zone. Future infrared sensors necessary for this ability are also inspired by the natural infrared receptors of Melanophila beetles.

A description of the fine structure of the infrared radiation (IR) sensor of Melanophila acuminata (De Geer) and of the role of the wings during flight in mechanically modulating incoming IR into on and off pulses, supports a thermopneumatic model of IR perception by this insect. The model postulates that pulsed IR, corresponding to wavelengths emitted by fires, enters an enclosed, airtight, thick-walled cavity in each sensor through an apical epicuticular waveguide and is absorbed by a thin, chitinous endocuticular lamella of the cavity wall. The lamella is heated and in turn heats and expands the enclosed air that then compresses a basal cuticular cap that displaces the tubular body of the sensor, triggering a dendritic impulse and transducing an action potential in the neuron. This process is possible because of the absorption by the chitinous lamella of the wavelengths of IR emitted by fires resulting in extraordinary IR wavelength discrimination, radiant energy sensitivity, and rapid response time. These properties distinguish the sensor from temperature sensors of insects, sometimes erroneously designated as IR sensors, that respond relatively slowly to broadband wavelength radiation.

The phloeo-cambiophagous buprestid Melanophila knoteki knoteki (Reitt.) var. hellenica (Obenberger.) is not a primary factor of fir decline problem although the beetle substantially contributes to Greek fir Abies cephalonica Loud. var. graeca (Fraas) Liu mortality. By using mapping depiction of the exit holes of the insect on a set of fir trees located on a line transect in a randomized point-centred quarter scheme and employing pattern analysis techniques we were able to reveal various scales of the infestation pattern. Four scales were recognized, two of them corresponding to the pattern of microsite selection on the bark of a fir tree. While the dispersed exit holes exhibited a statistically significant random dispersion on the bark, within each aggregation the pattern was uniform. The area of compartments created by Dirichlet partition approximated very well the sizes of the actual larval galleries. The Dirichlet tessellation of the bark space and the analysis of the parameter of the resulting partitions showed the predominance of the hexagonal conformation of the larval spaces when space was limited. When some exit holes were positioned close together it was found that they were directed away from each other so the resulting galleries were well separated. Several hypotheses are presented as to the mechanisms underpinning the observed patterns. The allocation of space is in accordance with the widely accepted ‘central place theory’ of W. Christaller, a general theory of pattern generated in the geographical dispersion of human settlements. The revealed pattern was also in accordance with the predictions of the theory of ‘central place foraging’ of R. H. MacArthur and the theory of ‘resource concentration hypothesis’ of R. Root.

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 contacts with ascending interneurons. Only a few collaterals appear to be involved in local (uniganglionic) circuits. About half of the neurons send their axons further anterior to the prothoracic ganglion. A subset of these ascend to the subesophageal ganglion, and about 10% project to the brain. Anatomical similarities suggest that the infrared-sensitive neurons are derived from neurons supplying mechanosensory sensilla. The arborization pattern of the infrared afferents suggests that infrared information is processed and integrated upstream from the thoracic ganglia.

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.

Buprestid beetles of the genus Melanophila (Coleoptera: Buprestidae) possess paired thoracic pit organs. Each pit houses about 70 tightly packed infrared sensilla that enable the beetles to detect forest fires at long range. The cuticular apparatus of a single infrared sensillum consists of an endocuticular sphere with an average diameter of 15 μm. Each sphere is innervated from below by the dendritic outer segment of a single sensory neuron that shows the same ultrastructure as a typical hair mechanoreceptor (e.g., sensillum trichodeum). Several transitional stages between cuticular mechanoreceptors and infrared sensilla can be found in the neighbourhood of the infrared sensillum field (intermediate sensilla and so-called suppressed systems). First electrophysiological recordings show that the receptors at the bottom of the pit are true infrared receptors. The sensilla respond in a fast phasic manner to infrared radiation and even an exposition time of 2 ms is sufficient to release a single spike. All morphological and physiological findings suggest that the infrared sensilla have evolved from ordinary cuticular mechanoreceptors and that mechanical events are still part of the transduction process. A model about the possible function of the infrared receptors of Melanophila is presented.

The pyrophilous Australian "fire-beetle"Merimna atrata approaches forest fires and possesses abdominal infrared (IR) organs. Each round IR organ is centrally innervated by a sensory complex showing two different units: one thermoreceptive multipolar neuron and one mechanosensitive chordotonal organ (CO) consisting of two scolopidia. We investigated the CO and found that the scolopidia are mononematic (the scolopale cap remains below the cuticle) and monodynal (one sensory cell per scolopidium). The dendrites of the scolopidia extend anteriorly and are attached by their caps to the cuticle about in the middle of the absorbing area. Structural features at the site of innervation suggest that the CO measures minute thermal deformations caused by IR absorption. Therefore, an additional photomechanic component which has been described for the IR receptors of pyrophilous jewel beetles of the genus Melanophila can be proposed for the IR organ of Merimna. Because scolopidia can measure displacements in the subnanometer range, the CO may enhance the sensitivity of the IR organ. The sensory complex of the Merimna IR organ shows the same units and similar cuticular modifications as the tympanal organs of some noctuid moths. Therefore, a parallel evolution of insect ears and the Merimna IR organ is discussed.

Pyrophilous jewel beetles of the genus Melanophila approach forest fires and there is considerable evidence that these beetles can detect fires from great distances of more than 60 km. Because Melanophila beetles are equipped with infrared receptors and are also attracted by hot surfaces it can be concluded that these infrared receptors are used for fire detection.The sensitivity of the IR receptors is still unknown. The lowest threshold published so far is 0.6 W/m(2) which, however, cannot explain the detection of forest fires by IR radiation from distances larger than approximately 10 km. To investigate the possible sensitivity of the IR receptors we assumed that beetles use IR radiation for remote fire detection and we made use of a historic report about a big oil-tank fire in Coalinga, California, in 1924. IR emission of an oil-tank fire can be calculated by "pool fire" simulations which now are used for fire safety and risk analysis. Assuming that beetles were lured to the fire from the nearest forests 25 and 130 km away, our results show that detection from a distance of 25 km requires a threshold of the IR receptors of at least 3×10(-2) W/m(2). According to our investigations most beetles became aware of the fire from a distance of 130 km. In this case the threshold has to be 1.3×10(-4) W/m(2). Because such low IR intensities are buried in thermal noise we suggest that the infrared sensory system of Melanophila beetles utilizes stochastic resonance for the detection of weak IR radiation. Our simulations also suggest that the biological IR receptors might be even more sensitive than uncooled technical IR sensors. Thus a closer look into the mode of operation of the Melanophila IR receptors seems promising for the development of novel IR sensors.

Beetles of the genus Melanophila approach forest fires from large distances away. For the detection of fires and of hot surfaces beetles have evolved infrared (IR) receptors, which have developed from common hair mechanoreceptors and are therefore termed photomechanic. Compared to a hair mechanoreceptor, a photomechanic IR sensillum shows the following two special features: (i) The formation of a complex cuticular sphere instead of the hair shaft; the sphere consists of an outer exocuticular shell as well as of a cavernous microfluidic core. (ii) The enclosure of the dendritic tip of the mechano-sensitive neuron inside the core in a liquid-filled chamber. Hence we propose that the photomechanic IR sensillum represents a microfluidic converter of infrared radiation to an increase of the pressure inside the sphere, which is in turn measured by a mechanosensitive neuron.

Beetles of the genus Melanophila and certain flat bugs of the genus Aradus approach forest fires. For the detection of fires and of hot surfaces the pyrophilous species of both genera have developed infrared (IR) receptors, which have developed from common hair mechanoreceptors. Thus this type of insect IR receptor has been termed photomechanic and shows the following two special features: (i) the formation of a complex cuticular sphere consisting of an outer exocuticular shell as well as of a cavernous microfluidic core. (ii) The enclosure of the dendritic tip of a mechanosensitive neuron inside the core in a liquid-filled chamber. Most probably a photomechanic IR sensillum acts as a microfluidic converter of infrared radiation into an increase in internal pressure inside the sphere, which is measured by a mechanosensitive neuron. A simple model for this biological IR sensor is the Golay sensor, which is filled with a liquid instead of gas. Here the absorbed IR radiation results in a pressure increase of the liquid and the deflection of a thin membrane. For the evaluation of this model analytical formulas are presented, which permits the calculation of the pressure increase in the cavity, the deformation of the membrane and the time constant of an artificial leak to compensate ambient temperature changes. Some organic liquids with high thermal expansion coefficients may improve the deflection of the membrane compared to water.

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 albicornis. In our study we investigated 10 Aradus species, once again including A. albicornis, and found prothoracic as well as hitherto unknown mesothoracic IR sensilla in A. albicornis, Aradus lugubris and Aradus fuscicornis. In Aradus flavicornis only prothoracic IR receptors were found. Currently the latter two species are not known as pyrophilous. However, there is considerable evidence that these flat bugs also approach forest fires. In all four species where IR receptors were identified, the dome-shaped IR sensilla look very similar. An IR sensillum consists of an internal exocuticular sphere reinforced by consecutive layers of chitin fibres. In the center of the sphere, a microfluidic core is located which consists of a cup-shaped plug of cuticle and an underlying fluid filled annular channel surrounding the tip of the dendrite of a mechanosensitive neuron. Like the IR receptors of buprestid beetles of the genus Melanophila, the IR sensilla found in Aradus species can be classified as photomechanic IR receptors.

For the detection of forest fires the "fire-loving" (pyrophilous) jewel beetle Melanophila acuminata uses a pair of sensor arrays each consisting of about 90 infrared (IR) receptors which are located on either sides of the body. The IR receptors most likely have evolved from common contact hair mechanoreceptors. Compared to a mechanoreceptor, an IR receptor shows the following special features: (i) the formation of a complex cuticular sphere instead of the bristle; the sphere consists of a hard outer exocuticular shell as well as of an inner softer and spongy mesocuticular core. (ii) The enclosure of the dendritic tip of the mechanosensitive neuron inside the sphere in a fluid-filled inner pressure chamber which is connected with the system of microcavities and nanocanals in the mesocuticular core. Hence we propose that an IR sensillum most probably acts as a microfluidic converter of infrared radiation into an increase in internal pressure inside the sphere which is measured by the mechanosensitive neuron. Because the miniaturized receptors respond within a few milliseconds to a brief pulse of IR radiation an approach is made to develop technical IR sensors based on the Melanophila IR receptors. Numerical simulations of sensor performance suggest that the sensitivity of a single IR receptor is in the range of 15 mW/cm2. Theoretical calculations which are based on a hypothetical fire of defined temperature and size demonstrate that a beetle should be able to detect a forest fire from a distance of 10 km. A fluidfilled Golay cell was taken as a basis for the design of a first sensor prototype.

An illustrated key for the identification of the Turkish species of the genus Melanophila Eschscholtz is given. A new subspecies, Melanophila knoteki turcica, is described from southern Turkey. The distribution, faunistics and habits of all the recorded species are discussed.