4 Material und Umwelt
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- 4.1 Biologische Materialschädigung und Referenzorganismen (18) (entfernen)
Chemical-free pest control by dielectric
heating with radio waves and microwaves:
Thermal effects
(2018)
Thermal pest control with hot air is widely accepted as an alternative to chemical methods. However, it requires relatively long treatment times owing to the low thermal conductivity of wood. Direct dielectric heating that applies radio waves or microwaves has the advantage of more homogeneous heating. However, Sound experimental data on this technique are currently rare. Therefore, the thermal treatment of wood-destroying insects with radio waves and microwaves was studied with two model pests, Anobium punctatum and Hylotrupes bajulus, and with Tenebrio molitor as a reference. The secure elimination of pests was achieved, and the corresponding treatment time was in the range of a few minutes. Temperature profiles were more homogeneous when applying radio waves.
Viele Menschen erfreuen sich an Schmetterlingen. Besonders die farbfrohen Tagfalter lösen angenehme Gefühle aus. In der kulturellen Entomologie haben Schmetterlinge daher einen hohen Stellenwert, so auch in der schöngeistigen Literatur. Eine aktuelle stichprobenartige Untersuchung von 54 Büchern der deutschsprachigen Belletristik mit Insektenbezug im Titel oder auf dem Cover zeigte, dass sich zwei Drittel von ihnen des Schmetterlingnarrativs bedienten. Die folgende Analyse setzte das Ergebnis in einen historischen Bezug zur Verwendung von Insektenvorbildern in der Unterhaltungsliteratur und in Autorenbiografien. Die besondere Stellung der Schmetterlinge wird dabei geschichtlich als Relikt einer kulturellen Genese mit mythologisch-religiösen Wurzeln interpretiert. Im antiken Griechenland wurde die Bezeichnung Psyche mit bewusster Doppelbedeutung für Schmetterling und Seele verwendet. Im Hellenismus wurden die Seele und Seelenwesen wie z. B. die Daimons (Genien) oftmals mit Schmetterlingsflügeln dargestellt. Auch in den levantinischen Religionen wurden einzelne Gottheiten und Schutzgeister mit Flügeln nach Schmetterlingsart, jedoch aus Vogelfedern bestehend, abgebildet. Mit der Entstehung und Verbreitung der monotheistischen Lehren gingen viele dieser geflügelten Glaubenswesen dann in die Engelschöre über. Auch wenn die Flügel der Engel letztendlich wahrscheinlich von denen der Vögel abzuleiten sind, bleibt ein starker emotionaler Bezug zu den Schmetterlingen, der weit über den rein ästhetischen ausstrahlt.
A short natural and cultural history of the webbing clothes moth (Tineola bisselliella). It is generally accepted that the natural habitats of most pest insects can be found outside the synanthropic environment in layers of leaf litter, under bark, as well as in rodent or bird nests. Indeed, most of the common fabric pests have been reported as being facultative nidicolous. Therefore, infestation of commodities by pest insects out of these reservoirs is one possibility to be considered. However, the likelihood of a pest´s occurrence and survival outside of the synanthropic habitat largely depends on its ecological potential and competitiveness against other species of the same ecological guild. Some pest species are rarely found in wild habitats, especially in those regions where they are not native and where they have been introduced by man.
The fabric pest Tineola bisselliella serves as a good example. Most likely originating from Central or Southern Africa, this insect was introduced into Europe probably not earlier than the late 18th century. Being more tolerant to dry environments than other fabric pests, its economical importance increased during the 20th century when the indoor climate changed because of central heating systems. Its occurrence in outdoor natural habitats must be regarded as accidental. Reported finds of webbing clothes moth larvae in bird nests e. g. have been largely overstated in the literature. Tineola bisselliella should be regarded as an invasive and eusynanthropic species in most parts of the world.
Second occurrence of aberrant antenna in house longhorn beetle Hylotrupes bajulus (Coleoptera: Cerambycidae) in the F3 generation. In 2016, the house longhorn beetle (Hylotrupes bajulus) breeding culture of the Federal Institute for Materials Research and Testing (BAM) in Berlin produced a second female beetle with a unique malformed right antenna similar to the one previously reported. As in the first case the flagellum following the pedical was bifurcated. This time, however, both branches were of similar length with 7 and 8 flagellomeres, respectively. The left antenna was normally developed with 11 antennal segments (scape, pedicel and 9 flagellomeres). This second female stands as F3-generation in direct maternal line to the previous one. A heritable cause for the malformation is likely.
Microbial communities in the immediate environment of socialized invertebrates can help to suppress pathogens, in part by synthesizing bioactive natural products. Here we characterized the core microbiomes of three termite species (genus Coptotermes) and their nest material to gain more insight into the diversity of termite-associated bacteria.
Sampling a healthy termite colony over time implicated a consolidated and highly stable microbiome, pointing toward the fact that beneficial bacterial phyla play a major role in termite fitness. In contrast, there was a significant shift in the composition of the core microbiome in one nest during a fungal infection, affecting the abundance of wellcharacterized Streptomyces species (phylum Actinobacteria) as well as less-studied bacterial phyla such as Acidobacteria. High-throughput cultivation in microplates was implemented to isolate and identify these less-studied bacterial phylogenetic group.
Amplicon sequencing confirmed that our method maintained the bacterial diversity of the environmental samples, enabling the isolation of novel Acidobacteriaceae and expanding the list of cultivated species to include two strains that may define new species within the genera Terracidiphilus and Acidobacterium.
Aim of study: In this study, natural durability of some domestic and foreign wood species against Hylotrupes bajulus and Anobium punctatum larvae were tested on laboratory scale
Area of study: This study was conducted at Department of Forest Products Engineering in Duzce University, Turkey and Federal Institute for Materials Research and Testing (BAM), Germany.
Material and Methods: Scotch pine (Pinus sylvestris), fir (Abies nordmanniana), spruce (Picea orientalis), cedar (Cedrus libani), poplar (Populus tremula) and beech (Fagus orientalis) woods were used to test H. bajulus larvae (EN 46-1). Alder (Alnus glutinosa), oak (Quercus cerris), poplar (Populus tremula), beech (Fagus orientalis), maple (Acer carpinifolium), ash (Fraxinus angustifolia), teak (Tectona grandis), ayous (Triplochiton scleroxylon), movingui (Distemonanthus benthamianus), dahoma (Piptadeniastrum africanum), iroko (Chlorophora excelsa), bubinga (Guibourtia tessmannii) and sapele (Entandrophragma cylindiricum) woods were used for A. punctatum larvae (EN 49-1). At the end of the experiment, the mortality rates of the larvae were determined and the size and weights of the surviving larvae were measured.
Main results: F. orientalis and C. libani were found to be the most resistant wood species against H. bajulus larvae while A. nordmanniana was the least resistant. All tropical wood species and oak and maple from domestic wood species showed 100% mortality rate therefore found to be the most resistant against A. punctatum larvae. The most vulnerable wood species was found to be alder with a 35% mortality.
Research highlights: while F. orientalis, C. libani, and P. tremula were found the most resistance wood species against H. bajulus, P. sylvestris and A. nordmanniana were determined as most vulnerable. All tropical wood species and two domestic species (Q. cerris and A. carpinifolium) showed the highest mortality rate as 100%. The least durable domestic wood was determined as alder.
Larvae and adults of Korynetes caeruleus (de Geer 1775) (Coleoptera: Cleridae) were collected from old churches and reared in the laboratory on Anobium punctatum (de Geer 1774) (Coleoptera: Ptinidae). Breeding success of K. caeruleus was low, but basic parameters of this species’ developmental cycle were identifi ed. At 21°C and 75% relative humidity and a fourmonth cold period at 4°C, the development of K. caeruleus from egg to adult appearance lasted 2 years. The pupal stage may be reached and completed after one and a half years. Feeding on larvae of A. punctatum by larvae of K. caeruleus was observed and consisted of a combination of sucking haemolymph and consuming body parts. The sickle-like mandibles of larvae of K. caeruleus penetrate the cuticle of prey larvae; this is followed by pumping and sucking body movements. Adult beetles of A. punctatum were not attacked by K. caeruleus larvae. Feeding behaviour of adult K. caeruleus was not investigated.
The evolutionary success of insects is promoted by their association with beneficial microbes that enable the utilization of unusual diets. The synanthropic clothing moth Tineola bisselliella provides an intriguing example of this phenomenon. The caterpillars of this species have adapted to feed on keratin-rich diets such as feathers and wool, which cannot be digested by most other animals and are resistant to common digestive enzymes. Inspired by the hypothesis that this ability may be conferred by symbiotic microbes, we utilized a simple assay to detect keratinase activity and a method to screen gut bacteria for candidate enzymes, which were isolated from feather-fed larvae. The isolation of DNA from keratin-degrading bacterial strains followed by de novo genome sequencing resulted in the identification of a novel bacterial strain related to Bacillus sp. FDAARGOS_235. Genome Annotation identified 20 genes with keratinase domains. Proteomic analysis of the culture supernatant from this gut bacterium grown in non-nutrient buffer supplemented with feathers revealed several candidate enzymes potentially responsible for keratin degradation, including a thiol-disulfide oxidoreductase and multiple proteases. Our results suggest that the unusual diet of T. bisselliella larvae promotes their association with keratinolytic microorganisms and that the ability of larvae to feed on keratin can at least partially be attributed to bacteria that produce a cocktail of keratin-degrading enzymes.
The clothes moth Tineola bisselliella is one of a few insects that can digest keratin, leading to the destruction of clothing, textiles and artwork. The mechanism of keratin digestion is not yet fully understood, partly reflecting the lack of publicly available genomic and transcriptomic data. Here we present a high-quality gut transcriptome of T. bisselliella generated from larvae reared on keratin-rich and keratin-free diets. The overall transcriptome consists of 428,221 contigs that were functionally annotated and screened for candidate enzymes involved in keratin utilization. As a mechanism for keratin digestion, we identified cysteine synthases, cystathionine β-synthases and cystathionine γ-lyases. These enzymes release hydrogen sulfite, which may reduce the disulfide bonds in keratin. The dataset also included 27 differentially expressed contigs with trypsin domains, among which 20 were associated with keratin feeding. Finally, we identified seven collagenases that were upregulated on the keratin-rich diet. In addition to this enzymatic repertoire potentially involved in breaking down keratin, our analysis of poly(A)-enriched and poly(A)-depleted transcripts suggested that T. bisselliella larvae possess an unstable intestinal microbiome that may nevertheless contribute to keratin digestion
Timber is constantly exposed to environmental influences under outdoor conditions which limits its Lifetime and usability. In order to counteract the damaging processes caused by insects, we have developed a novel and more environmentally friendly method to protect wood materials via covalent modification by organic insecticides. Starting with an important class of synthetic insecticides which are derived from the natural insecticide nicotine, various new carboxylic acid derivatives of imidacloprid were made accessible. These activated neonicotinoids were utilized for the chemical modification of wood hydroxy groups. In contrast to conventional wood preservation methods in which biocides are only physically bound to the surface for a limited time, the covalent fixation of the preservative guarantees a permanent effect against wood pests, demonstrated in standardized biological tests. Additionally, the environmental interaction caused by non-bound neonicotinoids is significantly reduced, since both, a smaller application rate is required and leaching of the active ingredient is prevented. By minimizing the pest infestation, the lifetime of the material increases while preserving the natural appearance of the material.